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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>7.6. LIMIT and OFFSET</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-order.html" title="7.5. Sorting Rows" /><link rel="next" href="queries-values.html" title="7.7. VALUES Lists" /></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">7.6. <code xmlns="http://www.w3.org/1999/xhtml" class="literal">LIMIT</code> and <code xmlns="http://www.w3.org/1999/xhtml" class="literal">OFFSET</code></th></tr><tr><td width="10%" align="left"><a accesskey="p" href="queries-order.html" title="7.5. Sorting Rows">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-values.html" title="7.7. VALUES Lists">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="QUERIES-LIMIT"><div class="titlepage"><div><div><h2 class="title" style="clear: both">7.6. <code class="literal">LIMIT</code> and <code class="literal">OFFSET</code></h2></div></div></div><a id="id-1.5.6.10.2" class="indexterm"></a><a id="id-1.5.6.10.3" class="indexterm"></a><p>
<code class="literal">LIMIT</code> and <code class="literal">OFFSET</code> allow you to retrieve just
a portion of the rows that are generated by the rest of the query:
</p><pre class="synopsis">
SELECT <em class="replaceable"><code>select_list</code></em>
FROM <em class="replaceable"><code>table_expression</code></em>
[<span class="optional"> ORDER BY ... </span>]
[<span class="optional"> LIMIT { <em class="replaceable"><code>number</code></em> | ALL } </span>] [<span class="optional"> OFFSET <em class="replaceable"><code>number</code></em> </span>]
</pre><p>
</p><p>
If a limit count is given, no more than that many rows will be
returned (but possibly fewer, if the query itself yields fewer rows).
<code class="literal">LIMIT ALL</code> is the same as omitting the <code class="literal">LIMIT</code>
clause, as is <code class="literal">LIMIT</code> with a NULL argument.
</p><p>
<code class="literal">OFFSET</code> says to skip that many rows before beginning to
return rows. <code class="literal">OFFSET 0</code> is the same as omitting the
<code class="literal">OFFSET</code> clause, as is <code class="literal">OFFSET</code> with a NULL argument.
</p><p>
If both <code class="literal">OFFSET</code>
and <code class="literal">LIMIT</code> appear, then <code class="literal">OFFSET</code> rows are
skipped before starting to count the <code class="literal">LIMIT</code> rows that
are returned.
</p><p>
When using <code class="literal">LIMIT</code>, it is important to use an
<code class="literal">ORDER BY</code> clause that constrains the result rows into a
unique order. Otherwise you will get an unpredictable subset of
the query's rows. You might be asking for the tenth through
twentieth rows, but tenth through twentieth in what ordering? The
ordering is unknown, unless you specified <code class="literal">ORDER BY</code>.
</p><p>
The query optimizer takes <code class="literal">LIMIT</code> into account when
generating query plans, so you are very likely to get different
plans (yielding different row orders) depending on what you give
for <code class="literal">LIMIT</code> and <code class="literal">OFFSET</code>. Thus, using
different <code class="literal">LIMIT</code>/<code class="literal">OFFSET</code> values to select
different subsets of a query result <span class="emphasis"><em>will give
inconsistent results</em></span> unless you enforce a predictable
result ordering with <code class="literal">ORDER BY</code>. This is not a bug; it
is an inherent consequence of the fact that SQL does not promise to
deliver the results of a query in any particular order unless
<code class="literal">ORDER BY</code> is used to constrain the order.
</p><p>
The rows skipped by an <code class="literal">OFFSET</code> clause still have to be
computed inside the server; therefore a large <code class="literal">OFFSET</code>
might be inefficient.
</p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="queries-order.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-values.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">7.5. Sorting Rows </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> 7.7. <code class="literal">VALUES</code> Lists</td></tr></table></div></body></html>
