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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>7.7. 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 id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">7.7. <code 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 15.7 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 /></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" title="7.6. LIMIT and OFFSET">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="queries.html" title="Chapter 7. Queries">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="queries-with.html" title="7.8. WITH Queries (Common Table Expressions)">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" title="PostgreSQL 15.7 Documentation">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>
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