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<title>9.18.Set Returning Functions</title>
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<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="sect1" lang="en">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="functions-srf"></a>9.18.Set Returning Functions</h2></div></div></div>
<a name="id621146"></a><a name="id621159"></a><p> This section describes functions that possibly return more than one row.
Currently the only functions in this class are series generating functions,
as detailed in <a href="functions-srf.html#functions-srf-series" title="Table9.38.Series Generating Functions">Table9.38, “Series Generating Functions”</a>.
</p>
<div class="table">
<a name="functions-srf-series"></a><p class="title"><b>Table9.38.Series Generating Functions</b></p>
<div class="table-contents"><table summary="Series Generating Functions" border="1">
<colgroup>
<col>
<col>
<col>
<col>
</colgroup>
<thead><tr>
<th>Function</th>
<th>Argument Type</th>
<th>Return Type</th>
<th>Description</th>
</tr></thead>
<tbody>
<tr>
<td><code class="literal"><code class="function">generate_series</code>(<em class="parameter"><code>start</code></em>, <em class="parameter"><code>stop</code></em>)</code></td>
<td>
<code class="type">int</code> or <code class="type">bigint</code>
</td>
<td>
<code class="type">setof int</code> or <code class="type">setof bigint</code> (same as argument type)</td>
<td> Generate a series of values, from <em class="parameter"><code>start</code></em> to <em class="parameter"><code>stop</code></em>
with a step size of one
</td>
</tr>
<tr>
<td><code class="literal"><code class="function">generate_series</code>(<em class="parameter"><code>start</code></em>, <em class="parameter"><code>stop</code></em>, <em class="parameter"><code>step</code></em>)</code></td>
<td>
<code class="type">int</code> or <code class="type">bigint</code>
</td>
<td>
<code class="type">setof int</code> or <code class="type">setof bigint</code> (same as argument type)</td>
<td> Generate a series of values, from <em class="parameter"><code>start</code></em> to <em class="parameter"><code>stop</code></em>
with a step size of <em class="parameter"><code>step</code></em>
</td>
</tr>
</tbody>
</table></div>
</div>
<br class="table-break"><p> When <em class="parameter"><code>step</code></em> is positive, zero rows are returned if
<em class="parameter"><code>start</code></em> is greater than <em class="parameter"><code>stop</code></em>.
Conversely, when <em class="parameter"><code>step</code></em> is negative, zero rows are
returned if <em class="parameter"><code>start</code></em> is less than <em class="parameter"><code>stop</code></em>.
Zero rows are also returned for <code class="literal">NULL</code> inputs. It is an error
for <em class="parameter"><code>step</code></em> to be zero. Some examples follow:
</p>
<pre class="programlisting">select * from generate_series(2,4);
generate_series
-----------------
2
3
4
(3 rows)
select * from generate_series(5,1,-2);
generate_series
-----------------
5
3
1
(3 rows)
select * from generate_series(4,3);
generate_series
-----------------
(0 rows)
select current_date + s.a as dates from generate_series(0,14,7) as s(a);
dates
------------
2004-02-05
2004-02-12
2004-02-19
(3 rows)</pre>
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