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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>9.4. String Functions and Operators</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="functions-math.html" title="9.3. Mathematical Functions and Operators" /><link rel="next" href="functions-binarystring.html" title="9.5. Binary String Functions and Operators" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">9.4. String Functions and Operators</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="functions-math.html" title="9.3. Mathematical Functions and Operators">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="functions.html" title="Chapter 9. Functions and Operators">Up</a></td><th width="60%" align="center">Chapter 9. Functions and Operators</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 11.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="functions-binarystring.html" title="9.5. Binary String Functions and Operators">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="FUNCTIONS-STRING"><div class="titlepage"><div><div><h2 class="title" style="clear: both">9.4. String Functions and Operators</h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="sect2"><a href="functions-string.html#FUNCTIONS-STRING-FORMAT">9.4.1. <code class="function">format</code></a></span></dt></dl></div><p>
This section describes functions and operators for examining and
manipulating string values. Strings in this context include values
of the types <code class="type">character</code>, <code class="type">character varying</code>,
and <code class="type">text</code>. Unless otherwise noted, all
of the functions listed below work on all of these types, but be
wary of potential effects of automatic space-padding when using the
<code class="type">character</code> type. Some functions also exist
natively for the bit-string types.
</p><p>
<acronym class="acronym">SQL</acronym> defines some string functions that use
key words, rather than commas, to separate
arguments. Details are in
<a class="xref" href="functions-string.html#FUNCTIONS-STRING-SQL" title="Table 9.8. SQL String Functions and Operators">Table 9.8</a>.
<span class="productname">PostgreSQL</span> also provides versions of these functions
that use the regular function invocation syntax
(see <a class="xref" href="functions-string.html#FUNCTIONS-STRING-OTHER" title="Table 9.9. Other String Functions">Table 9.9</a>).
</p><div class="note"><h3 class="title">Note</h3><p>
Before <span class="productname">PostgreSQL</span> 8.3, these functions would
silently accept values of several non-string data types as well, due to
the presence of implicit coercions from those data types to
<code class="type">text</code>. Those coercions have been removed because they frequently
caused surprising behaviors. However, the string concatenation operator
(<code class="literal">||</code>) still accepts non-string input, so long as at least one
input is of a string type, as shown in <a class="xref" href="functions-string.html#FUNCTIONS-STRING-SQL" title="Table 9.8. SQL String Functions and Operators">Table 9.8</a>. For other cases, insert an explicit
coercion to <code class="type">text</code> if you need to duplicate the previous behavior.
</p></div><div class="table" id="FUNCTIONS-STRING-SQL"><p class="title"><strong>Table 9.8. <acronym class="acronym">SQL</acronym> String Functions and Operators</strong></p><div class="table-contents"><table class="table" summary="SQL String Functions and Operators" border="1"><colgroup><col /><col /><col /><col /><col /></colgroup><thead><tr><th>Function</th><th>Return Type</th><th>Description</th><th>Example</th><th>Result</th></tr></thead><tbody><tr><td><code class="literal"><em class="parameter"><code>string</code></em> <code class="literal">||</code>
<em class="parameter"><code>string</code></em></code></td><td> <code class="type">text</code> </td><td>
String concatenation
<a id="id-1.5.8.9.5.2.2.1.3.1" class="indexterm"></a>
</td><td><code class="literal">'Post' || 'greSQL'</code></td><td><code class="literal">PostgreSQL</code></td></tr><tr><td>
<code class="literal"><em class="parameter"><code>string</code></em> <code class="literal">||</code>
<em class="parameter"><code>non-string</code></em></code>
or
<code class="literal"><em class="parameter"><code>non-string</code></em> <code class="literal">||</code>
<em class="parameter"><code>string</code></em></code>
</td><td> <code class="type">text</code> </td><td>
String concatenation with one non-string input
</td><td><code class="literal">'Value: ' || 42</code></td><td><code class="literal">Value: 42</code></td></tr><tr><td>
<a id="id-1.5.8.9.5.2.2.3.1.1" class="indexterm"></a>
<code class="literal"><code class="function">bit_length(<em class="parameter"><code>string</code></em>)</code></code>
</td><td><code class="type">int</code></td><td>Number of bits in string</td><td><code class="literal">bit_length('jose')</code></td><td><code class="literal">32</code></td></tr><tr><td>
<a id="id-1.5.8.9.5.2.2.4.1.1" class="indexterm"></a>
<code class="literal"><code class="function">char_length(<em class="parameter"><code>string</code></em>)</code></code> or <code class="literal"><code class="function">character_length(<em class="parameter"><code>string</code></em>)</code></code>
</td><td><code class="type">int</code></td><td>
Number of characters in string
<a id="id-1.5.8.9.5.2.2.4.3.1" class="indexterm"></a>
<a id="id-1.5.8.9.5.2.2.4.3.2" class="indexterm"></a>
</td><td><code class="literal">char_length('jose')</code></td><td><code class="literal">4</code></td></tr><tr><td>
<a id="id-1.5.8.9.5.2.2.5.1.1" class="indexterm"></a>
<code class="literal"><code class="function">lower(<em class="parameter"><code>string</code></em>)</code></code>
</td><td><code class="type">text</code></td><td>Convert string to lower case</td><td><code class="literal">lower('TOM')</code></td><td><code class="literal">tom</code></td></tr><tr><td>
<a id="id-1.5.8.9.5.2.2.6.1.1" class="indexterm"></a>
<code class="literal"><code class="function">octet_length(<em class="parameter"><code>string</code></em>)</code></code>
</td><td><code class="type">int</code></td><td>Number of bytes in string</td><td><code class="literal">octet_length('jose')</code></td><td><code class="literal">4</code></td></tr><tr><td>
<a id="id-1.5.8.9.5.2.2.7.1.1" class="indexterm"></a>
<code class="literal"><code class="function">overlay(<em class="parameter"><code>string</code></em> placing <em class="parameter"><code>string</code></em> from <code class="type">int</code> [<span class="optional">for <code class="type">int</code></span>])</code></code>
</td><td><code class="type">text</code></td><td>
Replace substring
</td><td><code class="literal">overlay('Txxxxas' placing 'hom' from 2 for 4)</code></td><td><code class="literal">Thomas</code></td></tr><tr><td>
<a id="id-1.5.8.9.5.2.2.8.1.1" class="indexterm"></a>
<code class="literal"><code class="function">position(<em class="parameter"><code>substring</code></em> in <em class="parameter"><code>string</code></em>)</code></code>
</td><td><code class="type">int</code></td><td>Location of specified substring</td><td><code class="literal">position('om' in 'Thomas')</code></td><td><code class="literal">3</code></td></tr><tr><td>
<a id="id-1.5.8.9.5.2.2.9.1.1" class="indexterm"></a>
<code class="literal"><code class="function">substring(<em class="parameter"><code>string</code></em> [<span class="optional">from <code class="type">int</code></span>] [<span class="optional">for <code class="type">int</code></span>])</code></code>
</td><td><code class="type">text</code></td><td>
Extract substring
</td><td><code class="literal">substring('Thomas' from 2 for 3)</code></td><td><code class="literal">hom</code></td></tr><tr><td><code class="literal"><code class="function">substring(<em class="parameter"><code>string</code></em> from <em class="replaceable"><code>pattern</code></em>)</code></code></td><td><code class="type">text</code></td><td>
Extract substring matching POSIX regular expression. See
<a class="xref" href="functions-matching.html" title="9.7. Pattern Matching">Section 9.7</a> for more information on pattern
matching.
</td><td><code class="literal">substring('Thomas' from '...$')</code></td><td><code class="literal">mas</code></td></tr><tr><td><code class="literal"><code class="function">substring(<em class="parameter"><code>string</code></em> from <em class="replaceable"><code>pattern</code></em> for <em class="replaceable"><code>escape</code></em>)</code></code></td><td><code class="type">text</code></td><td>
Extract substring matching <acronym class="acronym">SQL</acronym> regular expression.
See <a class="xref" href="functions-matching.html" title="9.7. Pattern Matching">Section 9.7</a> for more information on
pattern matching.
</td><td><code class="literal">substring('Thomas' from '%#"o_a#"_' for '#')</code></td><td><code class="literal">oma</code></td></tr><tr><td>
<a id="id-1.5.8.9.5.2.2.12.1.1" class="indexterm"></a>
<code class="literal"><code class="function">trim([<span class="optional">leading | trailing | both</span>]
[<span class="optional"><em class="parameter"><code>characters</code></em></span>] from
<em class="parameter"><code>string</code></em>)</code></code>
</td><td><code class="type">text</code></td><td>
Remove the longest string containing only characters from
<em class="parameter"><code>characters</code></em> (a space by default) from the
start, end, or both ends (<code class="literal">both</code> is the default)
of <em class="parameter"><code>string</code></em>
</td><td><code class="literal">trim(both 'xyz' from 'yxTomxx')</code></td><td><code class="literal">Tom</code></td></tr><tr><td>
<code class="literal"><code class="function">trim([<span class="optional">leading | trailing
| both</span>] [<span class="optional">from</span>]
<em class="parameter"><code>string</code></em>
[<span class="optional">, <em class="parameter"><code>characters</code></em></span>]
)</code></code>
</td><td><code class="type">text</code></td><td>
Non-standard syntax for <code class="function">trim()</code>
</td><td><code class="literal">trim(both from 'yxTomxx', 'xyz')</code></td><td><code class="literal">Tom</code></td></tr><tr><td>
<a id="id-1.5.8.9.5.2.2.14.1.1" class="indexterm"></a>
<code class="literal"><code class="function">upper(<em class="parameter"><code>string</code></em>)</code></code>
</td><td><code class="type">text</code></td><td>Convert string to upper case</td><td><code class="literal">upper('tom')</code></td><td><code class="literal">TOM</code></td></tr></tbody></table></div></div><br class="table-break" /><p>
Additional string manipulation functions are available and are
listed in <a class="xref" href="functions-string.html#FUNCTIONS-STRING-OTHER" title="Table 9.9. Other String Functions">Table 9.9</a>. Some of them are used internally to implement the
<acronym class="acronym">SQL</acronym>-standard string functions listed in <a class="xref" href="functions-string.html#FUNCTIONS-STRING-SQL" title="Table 9.8. SQL String Functions and Operators">Table 9.8</a>.
</p><div class="table" id="FUNCTIONS-STRING-OTHER"><p class="title"><strong>Table 9.9. Other String Functions</strong></p><div class="table-contents"><table class="table" summary="Other String Functions" border="1"><colgroup><col /><col /><col /><col /><col /></colgroup><thead><tr><th>Function</th><th>Return Type</th><th>Description</th><th>Example</th><th>Result</th></tr></thead><tbody><tr><td>
<a id="id-1.5.8.9.7.2.2.1.1.1" class="indexterm"></a>
<code class="literal"><code class="function">ascii(<em class="parameter"><code>string</code></em>)</code></code>
</td><td><code class="type">int</code></td><td>
<acronym class="acronym">ASCII</acronym> code of the first character of the
argument. For <acronym class="acronym">UTF8</acronym> returns the Unicode code
point of the character. For other multibyte encodings, the
argument must be an <acronym class="acronym">ASCII</acronym> character.
</td><td><code class="literal">ascii('x')</code></td><td><code class="literal">120</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.2.1.1" class="indexterm"></a>
<code class="literal"><code class="function">btrim(<em class="parameter"><code>string</code></em> <code class="type">text</code>
[<span class="optional">, <em class="parameter"><code>characters</code></em> <code class="type">text</code></span>])</code></code>
</td><td><code class="type">text</code></td><td>
Remove the longest string consisting only of characters
in <em class="parameter"><code>characters</code></em> (a space by default)
from the start and end of <em class="parameter"><code>string</code></em>
</td><td><code class="literal">btrim('xyxtrimyyx', 'xyz')</code></td><td><code class="literal">trim</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.3.1.1" class="indexterm"></a>
<code class="literal"><code class="function">chr(<code class="type">int</code>)</code></code>
</td><td><code class="type">text</code></td><td>
Character with the given code. For <acronym class="acronym">UTF8</acronym> the
argument is treated as a Unicode code point. For other multibyte
encodings the argument must designate an
<acronym class="acronym">ASCII</acronym> character. The NULL (0) character is not
allowed because text data types cannot store such bytes.
</td><td><code class="literal">chr(65)</code></td><td><code class="literal">A</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.4.1.1" class="indexterm"></a>
<code class="literal"><code class="function">concat(<em class="parameter"><code>str</code></em> <code class="type">"any"</code>
[, <em class="parameter"><code>str</code></em> <code class="type">"any"</code> [, ...] ])</code></code>
</td><td><code class="type">text</code></td><td>
Concatenate the text representations of all the arguments.
NULL arguments are ignored.
</td><td><code class="literal">concat('abcde', 2, NULL, 22)</code></td><td><code class="literal">abcde222</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.5.1.1" class="indexterm"></a>
<code class="literal"><code class="function">concat_ws(<em class="parameter"><code>sep</code></em> <code class="type">text</code>,
<em class="parameter"><code>str</code></em> <code class="type">"any"</code>
[, <em class="parameter"><code>str</code></em> <code class="type">"any"</code> [, ...] ])</code></code>
</td><td><code class="type">text</code></td><td>
Concatenate all but the first argument with separators. The first
argument is used as the separator string. NULL arguments are ignored.
</td><td><code class="literal">concat_ws(',', 'abcde', 2, NULL, 22)</code></td><td><code class="literal">abcde,2,22</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.6.1.1" class="indexterm"></a>
<code class="literal"><code class="function">convert(<em class="parameter"><code>string</code></em> <code class="type">bytea</code>,
<em class="parameter"><code>src_encoding</code></em> <code class="type">name</code>,
<em class="parameter"><code>dest_encoding</code></em> <code class="type">name</code>)</code></code>
</td><td><code class="type">bytea</code></td><td>
Convert string to <em class="parameter"><code>dest_encoding</code></em>. The
original encoding is specified by
<em class="parameter"><code>src_encoding</code></em>. The
<em class="parameter"><code>string</code></em> must be valid in this encoding.
Conversions can be defined by <code class="command">CREATE CONVERSION</code>.
Also there are some predefined conversions. See <a class="xref" href="functions-string.html#CONVERSION-NAMES" title="Table 9.10. Built-in Conversions">Table 9.10</a> for available conversions.
</td><td><code class="literal">convert('text_in_utf8', 'UTF8', 'LATIN1')</code></td><td><code class="literal">text_in_utf8</code> represented in Latin-1
encoding (ISO 8859-1)</td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.7.1.1" class="indexterm"></a>
<code class="literal"><code class="function">convert_from(<em class="parameter"><code>string</code></em> <code class="type">bytea</code>,
<em class="parameter"><code>src_encoding</code></em> <code class="type">name</code>)</code></code>
</td><td><code class="type">text</code></td><td>
Convert string to the database encoding. The original encoding
is specified by <em class="parameter"><code>src_encoding</code></em>. The
<em class="parameter"><code>string</code></em> must be valid in this encoding.
</td><td><code class="literal">convert_from('text_in_utf8', 'UTF8')</code></td><td><code class="literal">text_in_utf8</code> represented in the current database encoding</td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.8.1.1" class="indexterm"></a>
<code class="literal"><code class="function">convert_to(<em class="parameter"><code>string</code></em> <code class="type">text</code>,
<em class="parameter"><code>dest_encoding</code></em> <code class="type">name</code>)</code></code>
</td><td><code class="type">bytea</code></td><td>
Convert string to <em class="parameter"><code>dest_encoding</code></em>.
</td><td><code class="literal">convert_to('some text', 'UTF8')</code></td><td><code class="literal">some text</code> represented in the UTF8 encoding</td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.9.1.1" class="indexterm"></a>
<code class="literal"><code class="function">decode(<em class="parameter"><code>string</code></em> <code class="type">text</code>,
<em class="parameter"><code>format</code></em> <code class="type">text</code>)</code></code>
</td><td><code class="type">bytea</code></td><td>
Decode binary data from textual representation in <em class="parameter"><code>string</code></em>.
Options for <em class="parameter"><code>format</code></em> are same as in <code class="function">encode</code>.
</td><td><code class="literal">decode('MTIzAAE=', 'base64')</code></td><td><code class="literal">\x3132330001</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.10.1.1" class="indexterm"></a>
<code class="literal"><code class="function">encode(<em class="parameter"><code>data</code></em> <code class="type">bytea</code>,
<em class="parameter"><code>format</code></em> <code class="type">text</code>)</code></code>
</td><td><code class="type">text</code></td><td>
Encode binary data into a textual representation. Supported
formats are: <code class="literal">base64</code>, <code class="literal">hex</code>, <code class="literal">escape</code>.
<code class="literal">escape</code> converts zero bytes and high-bit-set bytes to
octal sequences (<code class="literal">\</code><em class="replaceable"><code>nnn</code></em>) and
doubles backslashes.
</td><td><code class="literal">encode('123\000\001', 'base64')</code></td><td><code class="literal">MTIzAAE=</code></td></tr><tr><td id="FORMAT">
<a id="id-1.5.8.9.7.2.2.11.1.1" class="indexterm"></a>
<code class="literal"><code class="function">format</code>(<em class="parameter"><code>formatstr</code></em> <code class="type">text</code>
[, <em class="parameter"><code>formatarg</code></em> <code class="type">"any"</code> [, ...] ])</code>
</td><td><code class="type">text</code></td><td>
Format arguments according to a format string.
This function is similar to the C function <code class="function">sprintf</code>.
See <a class="xref" href="functions-string.html#FUNCTIONS-STRING-FORMAT" title="9.4.1. format">Section 9.4.1</a>.
</td><td><code class="literal">format('Hello %s, %1$s', 'World')</code></td><td><code class="literal">Hello World, World</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.12.1.1" class="indexterm"></a>
<code class="literal"><code class="function">initcap(<em class="parameter"><code>string</code></em>)</code></code>
</td><td><code class="type">text</code></td><td>
Convert the first letter of each word to upper case and the
rest to lower case. Words are sequences of alphanumeric
characters separated by non-alphanumeric characters.
</td><td><code class="literal">initcap('hi THOMAS')</code></td><td><code class="literal">Hi Thomas</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.13.1.1" class="indexterm"></a>
<code class="literal"><code class="function">left(<em class="parameter"><code>str</code></em> <code class="type">text</code>,
<em class="parameter"><code>n</code></em> <code class="type">int</code>)</code></code>
</td><td><code class="type">text</code></td><td>
Return first <em class="replaceable"><code>n</code></em> characters in the string. When <em class="replaceable"><code>n</code></em>
is negative, return all but last |<em class="replaceable"><code>n</code></em>| characters.
</td><td><code class="literal">left('abcde', 2)</code></td><td><code class="literal">ab</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.14.1.1" class="indexterm"></a>
<code class="literal"><code class="function">length(<em class="parameter"><code>string</code></em>)</code></code>
</td><td><code class="type">int</code></td><td>
Number of characters in <em class="parameter"><code>string</code></em>
</td><td><code class="literal">length('jose')</code></td><td><code class="literal">4</code></td></tr><tr><td><code class="literal"><code class="function">length(<em class="parameter"><code>string</code></em> <code class="type">bytea</code>,
<em class="parameter"><code>encoding</code></em> <code class="type">name</code> )</code></code></td><td><code class="type">int</code></td><td>
Number of characters in <em class="parameter"><code>string</code></em> in the given
<em class="parameter"><code>encoding</code></em>. The <em class="parameter"><code>string</code></em>
must be valid in this encoding.
</td><td><code class="literal">length('jose', 'UTF8')</code></td><td><code class="literal">4</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.16.1.1" class="indexterm"></a>
<code class="literal"><code class="function">lpad(<em class="parameter"><code>string</code></em> <code class="type">text</code>,
<em class="parameter"><code>length</code></em> <code class="type">int</code>
[<span class="optional">, <em class="parameter"><code>fill</code></em> <code class="type">text</code></span>])</code></code>
</td><td><code class="type">text</code></td><td>
Fill up the <em class="parameter"><code>string</code></em> to length
<em class="parameter"><code>length</code></em> by prepending the characters
<em class="parameter"><code>fill</code></em> (a space by default). If the
<em class="parameter"><code>string</code></em> is already longer than
<em class="parameter"><code>length</code></em> then it is truncated (on the
right).
</td><td><code class="literal">lpad('hi', 5, 'xy')</code></td><td><code class="literal">xyxhi</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.17.1.1" class="indexterm"></a>
<code class="literal"><code class="function">ltrim(<em class="parameter"><code>string</code></em> <code class="type">text</code>
[<span class="optional">, <em class="parameter"><code>characters</code></em> <code class="type">text</code></span>])</code></code>
</td><td><code class="type">text</code></td><td>
Remove the longest string containing only characters from
<em class="parameter"><code>characters</code></em> (a space by default) from the start of
<em class="parameter"><code>string</code></em>
</td><td><code class="literal">ltrim('zzzytest', 'xyz')</code></td><td><code class="literal">test</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.18.1.1" class="indexterm"></a>
<code class="literal"><code class="function">md5(<em class="parameter"><code>string</code></em>)</code></code>
</td><td><code class="type">text</code></td><td>
Calculates the MD5 hash of <em class="parameter"><code>string</code></em>,
returning the result in hexadecimal
</td><td><code class="literal">md5('abc')</code></td><td><code class="literal">900150983cd24fb0 d6963f7d28e17f72</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.19.1.1" class="indexterm"></a>
<code class="literal"><code class="function">parse_ident(<em class="parameter"><code>qualified_identifier</code></em> <code class="type">text</code>
[, <em class="parameter"><code>strictmode</code></em> <code class="type">boolean</code> DEFAULT true ] )</code></code>
</td><td><code class="type">text[]</code></td><td>
Split <em class="parameter"><code>qualified_identifier</code></em> into an array of
identifiers, removing any quoting of individual identifiers. By
default, extra characters after the last identifier are considered an
error; but if the second parameter is <code class="literal">false</code>, then such
extra characters are ignored. (This behavior is useful for parsing
names for objects like functions.) Note that this function does not
truncate over-length identifiers. If you want truncation you can cast
the result to <code class="type">name[]</code>.
</td><td><code class="literal">parse_ident('"SomeSchema".someTable')</code></td><td><code class="literal">{SomeSchema,sometable}</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.20.1.1" class="indexterm"></a>
<code class="literal"><code class="function">pg_client_encoding()</code></code>
</td><td><code class="type">name</code></td><td>
Current client encoding name
</td><td><code class="literal">pg_client_encoding()</code></td><td><code class="literal">SQL_ASCII</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.21.1.1" class="indexterm"></a>
<code class="literal"><code class="function">quote_ident(<em class="parameter"><code>string</code></em> <code class="type">text</code>)</code></code>
</td><td><code class="type">text</code></td><td>
Return the given string suitably quoted to be used as an identifier
in an <acronym class="acronym">SQL</acronym> statement string.
Quotes are added only if necessary (i.e., if the string contains
non-identifier characters or would be case-folded).
Embedded quotes are properly doubled.
See also <a class="xref" href="plpgsql-statements.html#PLPGSQL-QUOTE-LITERAL-EXAMPLE" title="Example 43.1. Quoting Values In Dynamic Queries">Example 43.1</a>.
</td><td><code class="literal">quote_ident('Foo bar')</code></td><td><code class="literal">"Foo bar"</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.22.1.1" class="indexterm"></a>
<code class="literal"><code class="function">quote_literal(<em class="parameter"><code>string</code></em> <code class="type">text</code>)</code></code>
</td><td><code class="type">text</code></td><td>
Return the given string suitably quoted to be used as a string literal
in an <acronym class="acronym">SQL</acronym> statement string.
Embedded single-quotes and backslashes are properly doubled.
Note that <code class="function">quote_literal</code> returns null on null
input; if the argument might be null,
<code class="function">quote_nullable</code> is often more suitable.
See also <a class="xref" href="plpgsql-statements.html#PLPGSQL-QUOTE-LITERAL-EXAMPLE" title="Example 43.1. Quoting Values In Dynamic Queries">Example 43.1</a>.
</td><td><code class="literal">quote_literal(E'O\'Reilly')</code></td><td><code class="literal">'O''Reilly'</code></td></tr><tr><td><code class="literal"><code class="function">quote_literal(<em class="parameter"><code>value</code></em> <code class="type">anyelement</code>)</code></code></td><td><code class="type">text</code></td><td>
Coerce the given value to text and then quote it as a literal.
Embedded single-quotes and backslashes are properly doubled.
</td><td><code class="literal">quote_literal(42.5)</code></td><td><code class="literal">'42.5'</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.24.1.1" class="indexterm"></a>
<code class="literal"><code class="function">quote_nullable(<em class="parameter"><code>string</code></em> <code class="type">text</code>)</code></code>
</td><td><code class="type">text</code></td><td>
Return the given string suitably quoted to be used as a string literal
in an <acronym class="acronym">SQL</acronym> statement string; or, if the argument
is null, return <code class="literal">NULL</code>.
Embedded single-quotes and backslashes are properly doubled.
See also <a class="xref" href="plpgsql-statements.html#PLPGSQL-QUOTE-LITERAL-EXAMPLE" title="Example 43.1. Quoting Values In Dynamic Queries">Example 43.1</a>.
</td><td><code class="literal">quote_nullable(NULL)</code></td><td><code class="literal">NULL</code></td></tr><tr><td><code class="literal"><code class="function">quote_nullable(<em class="parameter"><code>value</code></em> <code class="type">anyelement</code>)</code></code></td><td><code class="type">text</code></td><td>
Coerce the given value to text and then quote it as a literal;
or, if the argument is null, return <code class="literal">NULL</code>.
Embedded single-quotes and backslashes are properly doubled.
</td><td><code class="literal">quote_nullable(42.5)</code></td><td><code class="literal">'42.5'</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.26.1.1" class="indexterm"></a>
<code class="literal"><code class="function">regexp_match(<em class="parameter"><code>string</code></em> <code class="type">text</code>, <em class="parameter"><code>pattern</code></em> <code class="type">text</code> [, <em class="parameter"><code>flags</code></em> <code class="type">text</code>])</code></code>
</td><td><code class="type">text[]</code></td><td>
Return captured substring(s) resulting from the first match of a POSIX
regular expression to the <em class="parameter"><code>string</code></em>. See
<a class="xref" href="functions-matching.html#FUNCTIONS-POSIX-REGEXP" title="9.7.3. POSIX Regular Expressions">Section 9.7.3</a> for more information.
</td><td><code class="literal">regexp_match('foobarbequebaz', '(bar)(beque)')</code></td><td><code class="literal">{bar,beque}</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.27.1.1" class="indexterm"></a>
<code class="literal"><code class="function">regexp_matches(<em class="parameter"><code>string</code></em> <code class="type">text</code>, <em class="parameter"><code>pattern</code></em> <code class="type">text</code> [, <em class="parameter"><code>flags</code></em> <code class="type">text</code>])</code></code>
</td><td><code class="type">setof text[]</code></td><td>
Return captured substring(s) resulting from matching a POSIX regular
expression to the <em class="parameter"><code>string</code></em>. See
<a class="xref" href="functions-matching.html#FUNCTIONS-POSIX-REGEXP" title="9.7.3. POSIX Regular Expressions">Section 9.7.3</a> for more information.
</td><td><code class="literal">regexp_matches('foobarbequebaz', 'ba.', 'g')</code></td><td><code class="literal">{bar}</code><p><code class="literal">{baz}</code></p> (2 rows)</td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.28.1.1" class="indexterm"></a>
<code class="literal"><code class="function">regexp_replace(<em class="parameter"><code>string</code></em> <code class="type">text</code>, <em class="parameter"><code>pattern</code></em> <code class="type">text</code>, <em class="parameter"><code>replacement</code></em> <code class="type">text</code> [, <em class="parameter"><code>flags</code></em> <code class="type">text</code>])</code></code>
</td><td><code class="type">text</code></td><td>
Replace substring(s) matching a POSIX regular expression. See
<a class="xref" href="functions-matching.html#FUNCTIONS-POSIX-REGEXP" title="9.7.3. POSIX Regular Expressions">Section 9.7.3</a> for more information.
</td><td><code class="literal">regexp_replace('Thomas', '.[mN]a.', 'M')</code></td><td><code class="literal">ThM</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.29.1.1" class="indexterm"></a>
<code class="literal"><code class="function">regexp_split_to_array(<em class="parameter"><code>string</code></em> <code class="type">text</code>, <em class="parameter"><code>pattern</code></em> <code class="type">text</code> [, <em class="parameter"><code>flags</code></em> <code class="type">text</code> ])</code></code>
</td><td><code class="type">text[]</code></td><td>
Split <em class="parameter"><code>string</code></em> using a POSIX regular expression as
the delimiter. See <a class="xref" href="functions-matching.html#FUNCTIONS-POSIX-REGEXP" title="9.7.3. POSIX Regular Expressions">Section 9.7.3</a> for more
information.
</td><td><code class="literal">regexp_split_to_array('hello world', '\s+')</code></td><td><code class="literal">{hello,world}</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.30.1.1" class="indexterm"></a>
<code class="literal"><code class="function">regexp_split_to_table(<em class="parameter"><code>string</code></em> <code class="type">text</code>, <em class="parameter"><code>pattern</code></em> <code class="type">text</code> [, <em class="parameter"><code>flags</code></em> <code class="type">text</code>])</code></code>
</td><td><code class="type">setof text</code></td><td>
Split <em class="parameter"><code>string</code></em> using a POSIX regular expression as
the delimiter. See <a class="xref" href="functions-matching.html#FUNCTIONS-POSIX-REGEXP" title="9.7.3. POSIX Regular Expressions">Section 9.7.3</a> for more
information.
</td><td><code class="literal">regexp_split_to_table('hello world', '\s+')</code></td><td><code class="literal">hello</code><p><code class="literal">world</code></p> (2 rows)</td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.31.1.1" class="indexterm"></a>
<code class="literal"><code class="function">repeat(<em class="parameter"><code>string</code></em> <code class="type">text</code>, <em class="parameter"><code>number</code></em> <code class="type">int</code>)</code></code>
</td><td><code class="type">text</code></td><td>Repeat <em class="parameter"><code>string</code></em> the specified
<em class="parameter"><code>number</code></em> of times</td><td><code class="literal">repeat('Pg', 4)</code></td><td><code class="literal">PgPgPgPg</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.32.1.1" class="indexterm"></a>
<code class="literal"><code class="function">replace(<em class="parameter"><code>string</code></em> <code class="type">text</code>,
<em class="parameter"><code>from</code></em> <code class="type">text</code>,
<em class="parameter"><code>to</code></em> <code class="type">text</code>)</code></code>
</td><td><code class="type">text</code></td><td>Replace all occurrences in <em class="parameter"><code>string</code></em> of substring
<em class="parameter"><code>from</code></em> with substring <em class="parameter"><code>to</code></em>
</td><td><code class="literal">replace('abcdefabcdef', 'cd', 'XX')</code></td><td><code class="literal">abXXefabXXef</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.33.1.1" class="indexterm"></a>
<code class="literal"><code class="function">reverse(<em class="parameter"><code>str</code></em>)</code></code>
</td><td><code class="type">text</code></td><td>
Return reversed string.
</td><td><code class="literal">reverse('abcde')</code></td><td><code class="literal">edcba</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.34.1.1" class="indexterm"></a>
<code class="literal"><code class="function">right(<em class="parameter"><code>str</code></em> <code class="type">text</code>,
<em class="parameter"><code>n</code></em> <code class="type">int</code>)</code></code>
</td><td><code class="type">text</code></td><td>
Return last <em class="replaceable"><code>n</code></em> characters in the string. When <em class="replaceable"><code>n</code></em>
is negative, return all but first |<em class="replaceable"><code>n</code></em>| characters.
</td><td><code class="literal">right('abcde', 2)</code></td><td><code class="literal">de</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.35.1.1" class="indexterm"></a>
<code class="literal"><code class="function">rpad(<em class="parameter"><code>string</code></em> <code class="type">text</code>,
<em class="parameter"><code>length</code></em> <code class="type">int</code>
[<span class="optional">, <em class="parameter"><code>fill</code></em> <code class="type">text</code></span>])</code></code>
</td><td><code class="type">text</code></td><td>
Fill up the <em class="parameter"><code>string</code></em> to length
<em class="parameter"><code>length</code></em> by appending the characters
<em class="parameter"><code>fill</code></em> (a space by default). If the
<em class="parameter"><code>string</code></em> is already longer than
<em class="parameter"><code>length</code></em> then it is truncated.
</td><td><code class="literal">rpad('hi', 5, 'xy')</code></td><td><code class="literal">hixyx</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.36.1.1" class="indexterm"></a>
<code class="literal"><code class="function">rtrim(<em class="parameter"><code>string</code></em> <code class="type">text</code>
[<span class="optional">, <em class="parameter"><code>characters</code></em> <code class="type">text</code></span>])</code></code>
</td><td><code class="type">text</code></td><td>
Remove the longest string containing only characters from
<em class="parameter"><code>characters</code></em> (a space by default) from the end of
<em class="parameter"><code>string</code></em>
</td><td><code class="literal">rtrim('testxxzx', 'xyz')</code></td><td><code class="literal">test</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.37.1.1" class="indexterm"></a>
<code class="literal"><code class="function">split_part(<em class="parameter"><code>string</code></em> <code class="type">text</code>,
<em class="parameter"><code>delimiter</code></em> <code class="type">text</code>,
<em class="parameter"><code>field</code></em> <code class="type">int</code>)</code></code>
</td><td><code class="type">text</code></td><td>Split <em class="parameter"><code>string</code></em> on <em class="parameter"><code>delimiter</code></em>
and return the given field (counting from one)
</td><td><code class="literal">split_part('abc~@~def~@~ghi', '~@~', 2)</code></td><td><code class="literal">def</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.38.1.1" class="indexterm"></a>
<code class="literal"><code class="function">strpos(<em class="parameter"><code>string</code></em>, <em class="parameter"><code>substring</code></em>)</code></code>
</td><td><code class="type">int</code></td><td>
Location of specified substring (same as
<code class="literal">position(<em class="parameter"><code>substring</code></em> in
<em class="parameter"><code>string</code></em>)</code>, but note the reversed
argument order)
</td><td><code class="literal">strpos('high', 'ig')</code></td><td><code class="literal">2</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.39.1.1" class="indexterm"></a>
<code class="literal"><code class="function">substr(<em class="parameter"><code>string</code></em>, <em class="parameter"><code>from</code></em> [<span class="optional">, <em class="parameter"><code>count</code></em></span>])</code></code>
</td><td><code class="type">text</code></td><td>
Extract substring (same as
<code class="literal">substring(<em class="parameter"><code>string</code></em> from <em class="parameter"><code>from</code></em> for <em class="parameter"><code>count</code></em>)</code>)
</td><td><code class="literal">substr('alphabet', 3, 2)</code></td><td><code class="literal">ph</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.40.1.1" class="indexterm"></a>
<code class="literal"><code class="function">starts_with(<em class="parameter"><code>string</code></em>, <em class="parameter"><code>prefix</code></em>)</code></code>
</td><td><code class="type">bool</code></td><td>
Returns true if <em class="parameter"><code>string</code></em> starts with <em class="parameter"><code>prefix</code></em>.
</td><td><code class="literal">starts_with('alphabet', 'alph')</code></td><td><code class="literal">t</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.41.1.1" class="indexterm"></a>
<code class="literal"><code class="function">to_ascii(<em class="parameter"><code>string</code></em> <code class="type">text</code>
[<span class="optional">, <em class="parameter"><code>encoding</code></em> <code class="type">text</code></span>])</code></code>
</td><td><code class="type">text</code></td><td>
Convert <em class="parameter"><code>string</code></em> to <acronym class="acronym">ASCII</acronym> from another encoding
(only supports conversion from <code class="literal">LATIN1</code>, <code class="literal">LATIN2</code>, <code class="literal">LATIN9</code>,
and <code class="literal">WIN1250</code> encodings)
</td><td><code class="literal">to_ascii('Karel')</code></td><td><code class="literal">Karel</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.42.1.1" class="indexterm"></a>
<code class="literal"><code class="function">to_hex(<em class="parameter"><code>number</code></em> <code class="type">int</code>
or <code class="type">bigint</code>)</code></code>
</td><td><code class="type">text</code></td><td>Convert <em class="parameter"><code>number</code></em> to its equivalent hexadecimal
representation
</td><td><code class="literal">to_hex(2147483647)</code></td><td><code class="literal">7fffffff</code></td></tr><tr><td>
<a id="id-1.5.8.9.7.2.2.43.1.1" class="indexterm"></a>
<code class="literal"><code class="function">translate(<em class="parameter"><code>string</code></em> <code class="type">text</code>,
<em class="parameter"><code>from</code></em> <code class="type">text</code>,
<em class="parameter"><code>to</code></em> <code class="type">text</code>)</code></code>
</td><td><code class="type">text</code></td><td>
Any character in <em class="parameter"><code>string</code></em> that matches a
character in the <em class="parameter"><code>from</code></em> set is replaced by
the corresponding character in the <em class="parameter"><code>to</code></em>
set. If <em class="parameter"><code>from</code></em> is longer than
<em class="parameter"><code>to</code></em>, occurrences of the extra characters in
<em class="parameter"><code>from</code></em> are removed.
</td><td><code class="literal">translate('12345', '143', 'ax')</code></td><td><code class="literal">a2x5</code></td></tr></tbody></table></div></div><br class="table-break" /><p>
The <code class="function">concat</code>, <code class="function">concat_ws</code> and
<code class="function">format</code> functions are variadic, so it is possible to
pass the values to be concatenated or formatted as an array marked with
the <code class="literal">VARIADIC</code> keyword (see <a class="xref" href="xfunc-sql.html#XFUNC-SQL-VARIADIC-FUNCTIONS" title="38.5.5. SQL Functions with Variable Numbers of Arguments">Section 38.5.5</a>). The array's elements are
treated as if they were separate ordinary arguments to the function.
If the variadic array argument is NULL, <code class="function">concat</code>
and <code class="function">concat_ws</code> return NULL, but
<code class="function">format</code> treats a NULL as a zero-element array.
</p><p>
See also the aggregate function <code class="function">string_agg</code> in
<a class="xref" href="functions-aggregate.html" title="9.20. Aggregate Functions">Section 9.20</a>.
</p><div class="table" id="CONVERSION-NAMES"><p class="title"><strong>Table 9.10. Built-in Conversions</strong></p><div class="table-contents"><table class="table" summary="Built-in Conversions" border="1"><colgroup><col /><col /><col /></colgroup><thead><tr><th>Conversion Name
<a href="#ftn.id-1.5.8.9.10.2.1.1.1.1" class="footnote"><sup class="footnote" id="id-1.5.8.9.10.2.1.1.1.1">[a]</sup></a>
</th><th>Source Encoding</th><th>Destination Encoding</th></tr></thead><tbody><tr><td><code class="literal">ascii_to_mic</code></td><td><code class="literal">SQL_ASCII</code></td><td><code class="literal">MULE_INTERNAL</code></td></tr><tr><td><code class="literal">ascii_to_utf8</code></td><td><code class="literal">SQL_ASCII</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">big5_to_euc_tw</code></td><td><code class="literal">BIG5</code></td><td><code class="literal">EUC_TW</code></td></tr><tr><td><code class="literal">big5_to_mic</code></td><td><code class="literal">BIG5</code></td><td><code class="literal">MULE_INTERNAL</code></td></tr><tr><td><code class="literal">big5_to_utf8</code></td><td><code class="literal">BIG5</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">euc_cn_to_mic</code></td><td><code class="literal">EUC_CN</code></td><td><code class="literal">MULE_INTERNAL</code></td></tr><tr><td><code class="literal">euc_cn_to_utf8</code></td><td><code class="literal">EUC_CN</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">euc_jp_to_mic</code></td><td><code class="literal">EUC_JP</code></td><td><code class="literal">MULE_INTERNAL</code></td></tr><tr><td><code class="literal">euc_jp_to_sjis</code></td><td><code class="literal">EUC_JP</code></td><td><code class="literal">SJIS</code></td></tr><tr><td><code class="literal">euc_jp_to_utf8</code></td><td><code class="literal">EUC_JP</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">euc_kr_to_mic</code></td><td><code class="literal">EUC_KR</code></td><td><code class="literal">MULE_INTERNAL</code></td></tr><tr><td><code class="literal">euc_kr_to_utf8</code></td><td><code class="literal">EUC_KR</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">euc_tw_to_big5</code></td><td><code class="literal">EUC_TW</code></td><td><code class="literal">BIG5</code></td></tr><tr><td><code class="literal">euc_tw_to_mic</code></td><td><code class="literal">EUC_TW</code></td><td><code class="literal">MULE_INTERNAL</code></td></tr><tr><td><code class="literal">euc_tw_to_utf8</code></td><td><code class="literal">EUC_TW</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">gb18030_to_utf8</code></td><td><code class="literal">GB18030</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">gbk_to_utf8</code></td><td><code class="literal">GBK</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">iso_8859_10_to_utf8</code></td><td><code class="literal">LATIN6</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">iso_8859_13_to_utf8</code></td><td><code class="literal">LATIN7</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">iso_8859_14_to_utf8</code></td><td><code class="literal">LATIN8</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">iso_8859_15_to_utf8</code></td><td><code class="literal">LATIN9</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">iso_8859_16_to_utf8</code></td><td><code class="literal">LATIN10</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">iso_8859_1_to_mic</code></td><td><code class="literal">LATIN1</code></td><td><code class="literal">MULE_INTERNAL</code></td></tr><tr><td><code class="literal">iso_8859_1_to_utf8</code></td><td><code class="literal">LATIN1</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">iso_8859_2_to_mic</code></td><td><code class="literal">LATIN2</code></td><td><code class="literal">MULE_INTERNAL</code></td></tr><tr><td><code class="literal">iso_8859_2_to_utf8</code></td><td><code class="literal">LATIN2</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">iso_8859_2_to_windows_1250</code></td><td><code class="literal">LATIN2</code></td><td><code class="literal">WIN1250</code></td></tr><tr><td><code class="literal">iso_8859_3_to_mic</code></td><td><code class="literal">LATIN3</code></td><td><code class="literal">MULE_INTERNAL</code></td></tr><tr><td><code class="literal">iso_8859_3_to_utf8</code></td><td><code class="literal">LATIN3</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">iso_8859_4_to_mic</code></td><td><code class="literal">LATIN4</code></td><td><code class="literal">MULE_INTERNAL</code></td></tr><tr><td><code class="literal">iso_8859_4_to_utf8</code></td><td><code class="literal">LATIN4</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">iso_8859_5_to_koi8_r</code></td><td><code class="literal">ISO_8859_5</code></td><td><code class="literal">KOI8R</code></td></tr><tr><td><code class="literal">iso_8859_5_to_mic</code></td><td><code class="literal">ISO_8859_5</code></td><td><code class="literal">MULE_INTERNAL</code></td></tr><tr><td><code class="literal">iso_8859_5_to_utf8</code></td><td><code class="literal">ISO_8859_5</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">iso_8859_5_to_windows_1251</code></td><td><code class="literal">ISO_8859_5</code></td><td><code class="literal">WIN1251</code></td></tr><tr><td><code class="literal">iso_8859_5_to_windows_866</code></td><td><code class="literal">ISO_8859_5</code></td><td><code class="literal">WIN866</code></td></tr><tr><td><code class="literal">iso_8859_6_to_utf8</code></td><td><code class="literal">ISO_8859_6</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">iso_8859_7_to_utf8</code></td><td><code class="literal">ISO_8859_7</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">iso_8859_8_to_utf8</code></td><td><code class="literal">ISO_8859_8</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">iso_8859_9_to_utf8</code></td><td><code class="literal">LATIN5</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">johab_to_utf8</code></td><td><code class="literal">JOHAB</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">koi8_r_to_iso_8859_5</code></td><td><code class="literal">KOI8R</code></td><td><code class="literal">ISO_8859_5</code></td></tr><tr><td><code class="literal">koi8_r_to_mic</code></td><td><code class="literal">KOI8R</code></td><td><code class="literal">MULE_INTERNAL</code></td></tr><tr><td><code class="literal">koi8_r_to_utf8</code></td><td><code class="literal">KOI8R</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">koi8_r_to_windows_1251</code></td><td><code class="literal">KOI8R</code></td><td><code class="literal">WIN1251</code></td></tr><tr><td><code class="literal">koi8_r_to_windows_866</code></td><td><code class="literal">KOI8R</code></td><td><code class="literal">WIN866</code></td></tr><tr><td><code class="literal">koi8_u_to_utf8</code></td><td><code class="literal">KOI8U</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">mic_to_ascii</code></td><td><code class="literal">MULE_INTERNAL</code></td><td><code class="literal">SQL_ASCII</code></td></tr><tr><td><code class="literal">mic_to_big5</code></td><td><code class="literal">MULE_INTERNAL</code></td><td><code class="literal">BIG5</code></td></tr><tr><td><code class="literal">mic_to_euc_cn</code></td><td><code class="literal">MULE_INTERNAL</code></td><td><code class="literal">EUC_CN</code></td></tr><tr><td><code class="literal">mic_to_euc_jp</code></td><td><code class="literal">MULE_INTERNAL</code></td><td><code class="literal">EUC_JP</code></td></tr><tr><td><code class="literal">mic_to_euc_kr</code></td><td><code class="literal">MULE_INTERNAL</code></td><td><code class="literal">EUC_KR</code></td></tr><tr><td><code class="literal">mic_to_euc_tw</code></td><td><code class="literal">MULE_INTERNAL</code></td><td><code class="literal">EUC_TW</code></td></tr><tr><td><code class="literal">mic_to_iso_8859_1</code></td><td><code class="literal">MULE_INTERNAL</code></td><td><code class="literal">LATIN1</code></td></tr><tr><td><code class="literal">mic_to_iso_8859_2</code></td><td><code class="literal">MULE_INTERNAL</code></td><td><code class="literal">LATIN2</code></td></tr><tr><td><code class="literal">mic_to_iso_8859_3</code></td><td><code class="literal">MULE_INTERNAL</code></td><td><code class="literal">LATIN3</code></td></tr><tr><td><code class="literal">mic_to_iso_8859_4</code></td><td><code class="literal">MULE_INTERNAL</code></td><td><code class="literal">LATIN4</code></td></tr><tr><td><code class="literal">mic_to_iso_8859_5</code></td><td><code class="literal">MULE_INTERNAL</code></td><td><code class="literal">ISO_8859_5</code></td></tr><tr><td><code class="literal">mic_to_koi8_r</code></td><td><code class="literal">MULE_INTERNAL</code></td><td><code class="literal">KOI8R</code></td></tr><tr><td><code class="literal">mic_to_sjis</code></td><td><code class="literal">MULE_INTERNAL</code></td><td><code class="literal">SJIS</code></td></tr><tr><td><code class="literal">mic_to_windows_1250</code></td><td><code class="literal">MULE_INTERNAL</code></td><td><code class="literal">WIN1250</code></td></tr><tr><td><code class="literal">mic_to_windows_1251</code></td><td><code class="literal">MULE_INTERNAL</code></td><td><code class="literal">WIN1251</code></td></tr><tr><td><code class="literal">mic_to_windows_866</code></td><td><code class="literal">MULE_INTERNAL</code></td><td><code class="literal">WIN866</code></td></tr><tr><td><code class="literal">sjis_to_euc_jp</code></td><td><code class="literal">SJIS</code></td><td><code class="literal">EUC_JP</code></td></tr><tr><td><code class="literal">sjis_to_mic</code></td><td><code class="literal">SJIS</code></td><td><code class="literal">MULE_INTERNAL</code></td></tr><tr><td><code class="literal">sjis_to_utf8</code></td><td><code class="literal">SJIS</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">tcvn_to_utf8</code></td><td><code class="literal">WIN1258</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">uhc_to_utf8</code></td><td><code class="literal">UHC</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">utf8_to_ascii</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">SQL_ASCII</code></td></tr><tr><td><code class="literal">utf8_to_big5</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">BIG5</code></td></tr><tr><td><code class="literal">utf8_to_euc_cn</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">EUC_CN</code></td></tr><tr><td><code class="literal">utf8_to_euc_jp</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">EUC_JP</code></td></tr><tr><td><code class="literal">utf8_to_euc_kr</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">EUC_KR</code></td></tr><tr><td><code class="literal">utf8_to_euc_tw</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">EUC_TW</code></td></tr><tr><td><code class="literal">utf8_to_gb18030</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">GB18030</code></td></tr><tr><td><code class="literal">utf8_to_gbk</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">GBK</code></td></tr><tr><td><code class="literal">utf8_to_iso_8859_1</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">LATIN1</code></td></tr><tr><td><code class="literal">utf8_to_iso_8859_10</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">LATIN6</code></td></tr><tr><td><code class="literal">utf8_to_iso_8859_13</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">LATIN7</code></td></tr><tr><td><code class="literal">utf8_to_iso_8859_14</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">LATIN8</code></td></tr><tr><td><code class="literal">utf8_to_iso_8859_15</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">LATIN9</code></td></tr><tr><td><code class="literal">utf8_to_iso_8859_16</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">LATIN10</code></td></tr><tr><td><code class="literal">utf8_to_iso_8859_2</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">LATIN2</code></td></tr><tr><td><code class="literal">utf8_to_iso_8859_3</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">LATIN3</code></td></tr><tr><td><code class="literal">utf8_to_iso_8859_4</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">LATIN4</code></td></tr><tr><td><code class="literal">utf8_to_iso_8859_5</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">ISO_8859_5</code></td></tr><tr><td><code class="literal">utf8_to_iso_8859_6</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">ISO_8859_6</code></td></tr><tr><td><code class="literal">utf8_to_iso_8859_7</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">ISO_8859_7</code></td></tr><tr><td><code class="literal">utf8_to_iso_8859_8</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">ISO_8859_8</code></td></tr><tr><td><code class="literal">utf8_to_iso_8859_9</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">LATIN5</code></td></tr><tr><td><code class="literal">utf8_to_johab</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">JOHAB</code></td></tr><tr><td><code class="literal">utf8_to_koi8_r</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">KOI8R</code></td></tr><tr><td><code class="literal">utf8_to_koi8_u</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">KOI8U</code></td></tr><tr><td><code class="literal">utf8_to_sjis</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">SJIS</code></td></tr><tr><td><code class="literal">utf8_to_tcvn</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">WIN1258</code></td></tr><tr><td><code class="literal">utf8_to_uhc</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">UHC</code></td></tr><tr><td><code class="literal">utf8_to_windows_1250</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">WIN1250</code></td></tr><tr><td><code class="literal">utf8_to_windows_1251</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">WIN1251</code></td></tr><tr><td><code class="literal">utf8_to_windows_1252</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">WIN1252</code></td></tr><tr><td><code class="literal">utf8_to_windows_1253</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">WIN1253</code></td></tr><tr><td><code class="literal">utf8_to_windows_1254</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">WIN1254</code></td></tr><tr><td><code class="literal">utf8_to_windows_1255</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">WIN1255</code></td></tr><tr><td><code class="literal">utf8_to_windows_1256</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">WIN1256</code></td></tr><tr><td><code class="literal">utf8_to_windows_1257</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">WIN1257</code></td></tr><tr><td><code class="literal">utf8_to_windows_866</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">WIN866</code></td></tr><tr><td><code class="literal">utf8_to_windows_874</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">WIN874</code></td></tr><tr><td><code class="literal">windows_1250_to_iso_8859_2</code></td><td><code class="literal">WIN1250</code></td><td><code class="literal">LATIN2</code></td></tr><tr><td><code class="literal">windows_1250_to_mic</code></td><td><code class="literal">WIN1250</code></td><td><code class="literal">MULE_INTERNAL</code></td></tr><tr><td><code class="literal">windows_1250_to_utf8</code></td><td><code class="literal">WIN1250</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">windows_1251_to_iso_8859_5</code></td><td><code class="literal">WIN1251</code></td><td><code class="literal">ISO_8859_5</code></td></tr><tr><td><code class="literal">windows_1251_to_koi8_r</code></td><td><code class="literal">WIN1251</code></td><td><code class="literal">KOI8R</code></td></tr><tr><td><code class="literal">windows_1251_to_mic</code></td><td><code class="literal">WIN1251</code></td><td><code class="literal">MULE_INTERNAL</code></td></tr><tr><td><code class="literal">windows_1251_to_utf8</code></td><td><code class="literal">WIN1251</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">windows_1251_to_windows_866</code></td><td><code class="literal">WIN1251</code></td><td><code class="literal">WIN866</code></td></tr><tr><td><code class="literal">windows_1252_to_utf8</code></td><td><code class="literal">WIN1252</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">windows_1256_to_utf8</code></td><td><code class="literal">WIN1256</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">windows_866_to_iso_8859_5</code></td><td><code class="literal">WIN866</code></td><td><code class="literal">ISO_8859_5</code></td></tr><tr><td><code class="literal">windows_866_to_koi8_r</code></td><td><code class="literal">WIN866</code></td><td><code class="literal">KOI8R</code></td></tr><tr><td><code class="literal">windows_866_to_mic</code></td><td><code class="literal">WIN866</code></td><td><code class="literal">MULE_INTERNAL</code></td></tr><tr><td><code class="literal">windows_866_to_utf8</code></td><td><code class="literal">WIN866</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">windows_866_to_windows_1251</code></td><td><code class="literal">WIN866</code></td><td><code class="literal">WIN</code></td></tr><tr><td><code class="literal">windows_874_to_utf8</code></td><td><code class="literal">WIN874</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">euc_jis_2004_to_utf8</code></td><td><code class="literal">EUC_JIS_2004</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">utf8_to_euc_jis_2004</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">EUC_JIS_2004</code></td></tr><tr><td><code class="literal">shift_jis_2004_to_utf8</code></td><td><code class="literal">SHIFT_JIS_2004</code></td><td><code class="literal">UTF8</code></td></tr><tr><td><code class="literal">utf8_to_shift_jis_2004</code></td><td><code class="literal">UTF8</code></td><td><code class="literal">SHIFT_JIS_2004</code></td></tr><tr><td><code class="literal">euc_jis_2004_to_shift_jis_2004</code></td><td><code class="literal">EUC_JIS_2004</code></td><td><code class="literal">SHIFT_JIS_2004</code></td></tr><tr><td><code class="literal">shift_jis_2004_to_euc_jis_2004</code></td><td><code class="literal">SHIFT_JIS_2004</code></td><td><code class="literal">EUC_JIS_2004</code></td></tr></tbody><tbody class="footnotes"><tr><td colspan="3"><div id="ftn.id-1.5.8.9.10.2.1.1.1.1" class="footnote"><p><a href="#id-1.5.8.9.10.2.1.1.1.1" class="para"><sup class="para">[a] </sup></a>
The conversion names follow a standard naming scheme: The
official name of the source encoding with all
non-alphanumeric characters replaced by underscores, followed
by <code class="literal">_to_</code>, followed by the similarly processed
destination encoding name. Therefore, the names might deviate
from the customary encoding names.
</p></div></td></tr></tbody></table></div></div><br class="table-break" /><div class="sect2" id="FUNCTIONS-STRING-FORMAT"><div class="titlepage"><div><div><h3 class="title">9.4.1. <code class="function">format</code></h3></div></div></div><a id="id-1.5.8.9.11.2" class="indexterm"></a><p>
The function <code class="function">format</code> produces output formatted according to
a format string, in a style similar to the C function
<code class="function">sprintf</code>.
</p><p>
</p><pre class="synopsis">
<code class="function">format</code>(<em class="parameter"><code>formatstr</code></em> <code class="type">text</code> [, <em class="parameter"><code>formatarg</code></em> <code class="type">"any"</code> [, ...] ])
</pre><p>
<em class="replaceable"><code>formatstr</code></em> is a format string that specifies how the
result should be formatted. Text in the format string is copied
directly to the result, except where <em class="firstterm">format specifiers</em> are
used. Format specifiers act as placeholders in the string, defining how
subsequent function arguments should be formatted and inserted into the
result. Each <em class="replaceable"><code>formatarg</code></em> argument is converted to text
according to the usual output rules for its data type, and then formatted
and inserted into the result string according to the format specifier(s).
</p><p>
Format specifiers are introduced by a <code class="literal">%</code> character and have
the form
</p><pre class="synopsis">
%[<em class="replaceable"><code>position</code></em>][<em class="replaceable"><code>flags</code></em>][<em class="replaceable"><code>width</code></em>]<em class="replaceable"><code>type</code></em>
</pre><p>
where the component fields are:
</p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="replaceable"><code>position</code></em> (optional)</span></dt><dd><p>
A string of the form <code class="literal"><em class="replaceable"><code>n</code></em>$</code> where
<em class="replaceable"><code>n</code></em> is the index of the argument to print.
Index 1 means the first argument after
<em class="replaceable"><code>formatstr</code></em>. If the <em class="replaceable"><code>position</code></em> is
omitted, the default is to use the next argument in sequence.
</p></dd><dt><span class="term"><em class="replaceable"><code>flags</code></em> (optional)</span></dt><dd><p>
Additional options controlling how the format specifier's output is
formatted. Currently the only supported flag is a minus sign
(<code class="literal">-</code>) which will cause the format specifier's output to be
left-justified. This has no effect unless the <em class="replaceable"><code>width</code></em>
field is also specified.
</p></dd><dt><span class="term"><em class="replaceable"><code>width</code></em> (optional)</span></dt><dd><p>
Specifies the <span class="emphasis"><em>minimum</em></span> number of characters to use to
display the format specifier's output. The output is padded on the
left or right (depending on the <code class="literal">-</code> flag) with spaces as
needed to fill the width. A too-small width does not cause
truncation of the output, but is simply ignored. The width may be
specified using any of the following: a positive integer; an
asterisk (<code class="literal">*</code>) to use the next function argument as the
width; or a string of the form <code class="literal">*<em class="replaceable"><code>n</code></em>$</code> to
use the <em class="replaceable"><code>n</code></em>th function argument as the width.
</p><p>
If the width comes from a function argument, that argument is
consumed before the argument that is used for the format specifier's
value. If the width argument is negative, the result is left
aligned (as if the <code class="literal">-</code> flag had been specified) within a
field of length <code class="function">abs</code>(<em class="replaceable"><code>width</code></em>).
</p></dd><dt><span class="term"><em class="replaceable"><code>type</code></em> (required)</span></dt><dd><p>
The type of format conversion to use to produce the format
specifier's output. The following types are supported:
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
<code class="literal">s</code> formats the argument value as a simple
string. A null value is treated as an empty string.
</p></li><li class="listitem"><p>
<code class="literal">I</code> treats the argument value as an SQL
identifier, double-quoting it if necessary.
It is an error for the value to be null (equivalent to
<code class="function">quote_ident</code>).
</p></li><li class="listitem"><p>
<code class="literal">L</code> quotes the argument value as an SQL literal.
A null value is displayed as the string <code class="literal">NULL</code>, without
quotes (equivalent to <code class="function">quote_nullable</code>).
</p></li></ul></div><p>
</p></dd></dl></div><p>
</p><p>
In addition to the format specifiers described above, the special sequence
<code class="literal">%%</code> may be used to output a literal <code class="literal">%</code> character.
</p><p>
Here are some examples of the basic format conversions:
</p><pre class="screen">
SELECT format('Hello %s', 'World');
<em class="lineannotation"><span class="lineannotation">Result: </span></em><code class="computeroutput">Hello World</code>
SELECT format('Testing %s, %s, %s, %%', 'one', 'two', 'three');
<em class="lineannotation"><span class="lineannotation">Result: </span></em><code class="computeroutput">Testing one, two, three, %</code>
SELECT format('INSERT INTO %I VALUES(%L)', 'Foo bar', E'O\'Reilly');
<em class="lineannotation"><span class="lineannotation">Result: </span></em><code class="computeroutput">INSERT INTO "Foo bar" VALUES('O''Reilly')</code>
SELECT format('INSERT INTO %I VALUES(%L)', 'locations', 'C:\Program Files');
<em class="lineannotation"><span class="lineannotation">Result: </span></em><code class="computeroutput">INSERT INTO locations VALUES('C:\Program Files')</code>
</pre><p>
</p><p>
Here are examples using <em class="replaceable"><code>width</code></em> fields
and the <code class="literal">-</code> flag:
</p><pre class="screen">
SELECT format('|%10s|', 'foo');
<em class="lineannotation"><span class="lineannotation">Result: </span></em><code class="computeroutput">| foo|</code>
SELECT format('|%-10s|', 'foo');
<em class="lineannotation"><span class="lineannotation">Result: </span></em><code class="computeroutput">|foo |</code>
SELECT format('|%*s|', 10, 'foo');
<em class="lineannotation"><span class="lineannotation">Result: </span></em><code class="computeroutput">| foo|</code>
SELECT format('|%*s|', -10, 'foo');
<em class="lineannotation"><span class="lineannotation">Result: </span></em><code class="computeroutput">|foo |</code>
SELECT format('|%-*s|', 10, 'foo');
<em class="lineannotation"><span class="lineannotation">Result: </span></em><code class="computeroutput">|foo |</code>
SELECT format('|%-*s|', -10, 'foo');
<em class="lineannotation"><span class="lineannotation">Result: </span></em><code class="computeroutput">|foo |</code>
</pre><p>
</p><p>
These examples show use of <em class="replaceable"><code>position</code></em> fields:
</p><pre class="screen">
SELECT format('Testing %3$s, %2$s, %1$s', 'one', 'two', 'three');
<em class="lineannotation"><span class="lineannotation">Result: </span></em><code class="computeroutput">Testing three, two, one</code>
SELECT format('|%*2$s|', 'foo', 10, 'bar');
<em class="lineannotation"><span class="lineannotation">Result: </span></em><code class="computeroutput">| bar|</code>
SELECT format('|%1$*2$s|', 'foo', 10, 'bar');
<em class="lineannotation"><span class="lineannotation">Result: </span></em><code class="computeroutput">| foo|</code>
</pre><p>
</p><p>
Unlike the standard C function <code class="function">sprintf</code>,
<span class="productname">PostgreSQL</span>'s <code class="function">format</code> function allows format
specifiers with and without <em class="replaceable"><code>position</code></em> fields to be mixed
in the same format string. A format specifier without a
<em class="replaceable"><code>position</code></em> field always uses the next argument after the
last argument consumed.
In addition, the <code class="function">format</code> function does not require all
function arguments to be used in the format string.
For example:
</p><pre class="screen">
SELECT format('Testing %3$s, %2$s, %s', 'one', 'two', 'three');
<em class="lineannotation"><span class="lineannotation">Result: </span></em><code class="computeroutput">Testing three, two, three</code>
</pre><p>
</p><p>
The <code class="literal">%I</code> and <code class="literal">%L</code> format specifiers are particularly
useful for safely constructing dynamic SQL statements. See
<a class="xref" href="plpgsql-statements.html#PLPGSQL-QUOTE-LITERAL-EXAMPLE" title="Example 43.1. Quoting Values In Dynamic Queries">Example 43.1</a>.
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