<?xml version="1.0" encoding="UTF-8" standalone="no"?> <!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>7.7. VALUES Lists</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="queries-limit.html" title="7.6. LIMIT and OFFSET" /><link rel="next" href="queries-with.html" title="7.8. WITH Queries (Common Table Expressions)" /></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">7.7. <code xmlns="http://www.w3.org/1999/xhtml" class="literal">VALUES</code> Lists</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="queries-limit.html" title="7.6. LIMIT and OFFSET">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="queries.html" title="Chapter 7. Queries">Up</a></td><th width="60%" align="center">Chapter 7. Queries</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="queries-with.html" title="7.8. WITH Queries (Common Table Expressions)">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="QUERIES-VALUES"><div class="titlepage"><div><div><h2 class="title" style="clear: both">7.7. <code class="literal">VALUES</code> Lists</h2></div></div></div><a id="id-1.5.6.11.2" class="indexterm"></a><p> <code class="literal">VALUES</code> provides a way to generate a <span class="quote">“<span class="quote">constant table</span>”</span> that can be used in a query without having to actually create and populate a table on-disk. The syntax is </p><pre class="synopsis"> VALUES ( <em class="replaceable"><code>expression</code></em> [, ...] ) [, ...] </pre><p> Each parenthesized list of expressions generates a row in the table. The lists must all have the same number of elements (i.e., the number of columns in the table), and corresponding entries in each list must have compatible data types. The actual data type assigned to each column of the result is determined using the same rules as for <code class="literal">UNION</code> (see <a class="xref" href="typeconv-union-case.html" title="10.5. UNION, CASE, and Related Constructs">Section 10.5</a>). </p><p> As an example: </p><pre class="programlisting"> VALUES (1, 'one'), (2, 'two'), (3, 'three'); </pre><p> will return a table of two columns and three rows. It's effectively equivalent to: </p><pre class="programlisting"> SELECT 1 AS column1, 'one' AS column2 UNION ALL SELECT 2, 'two' UNION ALL SELECT 3, 'three'; </pre><p> By default, <span class="productname">PostgreSQL</span> assigns the names <code class="literal">column1</code>, <code class="literal">column2</code>, etc. to the columns of a <code class="literal">VALUES</code> table. The column names are not specified by the SQL standard and different database systems do it differently, so it's usually better to override the default names with a table alias list, like this: </p><pre class="programlisting"> => SELECT * FROM (VALUES (1, 'one'), (2, 'two'), (3, 'three')) AS t (num,letter); num | letter -----+-------- 1 | one 2 | two 3 | three (3 rows) </pre><p> </p><p> Syntactically, <code class="literal">VALUES</code> followed by expression lists is treated as equivalent to: </p><pre class="synopsis"> SELECT <em class="replaceable"><code>select_list</code></em> FROM <em class="replaceable"><code>table_expression</code></em> </pre><p> and can appear anywhere a <code class="literal">SELECT</code> can. For example, you can use it as part of a <code class="literal">UNION</code>, or attach a <em class="replaceable"><code>sort_specification</code></em> (<code class="literal">ORDER BY</code>, <code class="literal">LIMIT</code>, and/or <code class="literal">OFFSET</code>) to it. <code class="literal">VALUES</code> is most commonly used as the data source in an <code class="command">INSERT</code> command, and next most commonly as a subquery. </p><p> For more information see <a class="xref" href="sql-values.html" title="VALUES"><span class="refentrytitle">VALUES</span></a>. </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="queries-limit.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="queries.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="queries-with.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">7.6. <code class="literal">LIMIT</code> and <code class="literal">OFFSET</code> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> 7.8. <code class="literal">WITH</code> Queries (Common Table Expressions)</td></tr></table></div></body></html>
