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<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="sect1" lang="en">
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<div class="titlepage"><div><div><h2 class="title" style="clear: both">
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<a name="queries-limit"></a>7.6.�<code class="literal">LIMIT</code> and <code class="literal">OFFSET</code></h2></div></div></div>
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<a name="id583356"></a><a name="id583367"></a><p> <code class="literal">LIMIT</code> and <code class="literal">OFFSET</code> allow you to retrieve just
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a portion of the rows that are generated by the rest of the query:
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<pre class="synopsis">SELECT <em class="replaceable"><code>select_list</code></em>
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FROM <em class="replaceable"><code>table_expression</code></em>
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[<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>
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<p> If a limit count is given, no more than that many rows will be
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returned (but possibly less, if the query itself yields less rows).
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<code class="literal">LIMIT ALL</code> is the same as omitting the <code class="literal">LIMIT</code>
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<p> <code class="literal">OFFSET</code> says to skip that many rows before beginning to
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return rows. <code class="literal">OFFSET 0</code> is the same as
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omitting the <code class="literal">OFFSET</code> clause. If both <code class="literal">OFFSET</code>
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and <code class="literal">LIMIT</code> appear, then <code class="literal">OFFSET</code> rows are
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skipped before starting to count the <code class="literal">LIMIT</code> rows that
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<p> When using <code class="literal">LIMIT</code>, it is important to use an
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<code class="literal">ORDER BY</code> clause that constrains the result rows into a
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unique order. Otherwise you will get an unpredictable subset of
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the query's rows. You may be asking for the tenth through
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twentieth rows, but tenth through twentieth in what ordering? The
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ordering is unknown, unless you specified <code class="literal">ORDER BY</code>.
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<p> The query optimizer takes <code class="literal">LIMIT</code> into account when
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generating a query plan, so you are very likely to get different
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plans (yielding different row orders) depending on what you give
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for <code class="literal">LIMIT</code> and <code class="literal">OFFSET</code>. Thus, using
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different <code class="literal">LIMIT</code>/<code class="literal">OFFSET</code> values to select
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different subsets of a query result <span class="emphasis"><em>will give
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inconsistent results</em></span> unless you enforce a predictable
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result ordering with <code class="literal">ORDER BY</code>. This is not a bug; it
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is an inherent consequence of the fact that SQL does not promise to
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deliver the results of a query in any particular order unless
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<code class="literal">ORDER BY</code> is used to constrain the order.
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<p> The rows skipped by an <code class="literal">OFFSET</code> clause still have to be
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computed inside the server; therefore a large <code class="literal">OFFSET</code>
added
removed
docs/en_US/pg/queries-limit.html
