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diff --git a/doc/src/sgml/html/sql-values.html b/doc/src/sgml/html/sql-values.html new file mode 100644 index 0000000..ac0ad90 --- /dev/null +++ b/doc/src/sgml/html/sql-values.html @@ -0,0 +1,138 @@ +<?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>VALUES</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="sql-vacuum.html" title="VACUUM" /><link rel="next" href="reference-client.html" title="PostgreSQL Client Applications" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">VALUES</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="sql-vacuum.html" title="VACUUM">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="sql-commands.html" title="SQL Commands">Up</a></td><th width="60%" align="center">SQL Commands</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 15.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="reference-client.html" title="PostgreSQL Client Applications">Next</a></td></tr></table><hr /></div><div class="refentry" id="SQL-VALUES"><div class="titlepage"></div><a id="id-1.9.3.185.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle">VALUES</span></h2><p>VALUES — compute a set of rows</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis"> +VALUES ( <em class="replaceable"><code>expression</code></em> [, ...] ) [, ...] + [ ORDER BY <em class="replaceable"><code>sort_expression</code></em> [ ASC | DESC | USING <em class="replaceable"><code>operator</code></em> ] [, ...] ] + [ LIMIT { <em class="replaceable"><code>count</code></em> | ALL } ] + [ OFFSET <em class="replaceable"><code>start</code></em> [ ROW | ROWS ] ] + [ FETCH { FIRST | NEXT } [ <em class="replaceable"><code>count</code></em> ] { ROW | ROWS } ONLY ] +</pre></div><div class="refsect1" id="id-1.9.3.185.5"><h2>Description</h2><p> + <code class="command">VALUES</code> computes a row value or set of row values + specified by value expressions. It is most commonly used to generate + a <span class="quote">“<span class="quote">constant table</span>”</span> within a larger command, but it can be + used on its own. + </p><p> + When more than one row is specified, all the rows must have the same + number of elements. The data types of the resulting table's columns are + determined by combining the explicit or inferred types of the expressions + appearing in that column, 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> + Within larger commands, <code class="command">VALUES</code> is syntactically allowed + anywhere that <code class="command">SELECT</code> is. Because it is treated like a + <code class="command">SELECT</code> by the grammar, it is possible to use + the <code class="literal">ORDER BY</code>, <code class="literal">LIMIT</code> (or + equivalently <code class="literal">FETCH FIRST</code>), + and <code class="literal">OFFSET</code> clauses with a + <code class="command">VALUES</code> command. + </p></div><div class="refsect1" id="id-1.9.3.185.6"><h2>Parameters</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="replaceable"><code>expression</code></em></span></dt><dd><p> + A constant or expression to compute and insert at the indicated place + in the resulting table (set of rows). In a <code class="command">VALUES</code> list + appearing at the top level of an <code class="command">INSERT</code>, an + <em class="replaceable"><code>expression</code></em> can be replaced + by <code class="literal">DEFAULT</code> to indicate that the destination column's + default value should be inserted. <code class="literal">DEFAULT</code> cannot + be used when <code class="command">VALUES</code> appears in other contexts. + </p></dd><dt><span class="term"><em class="replaceable"><code>sort_expression</code></em></span></dt><dd><p> + An expression or integer constant indicating how to sort the result + rows. This expression can refer to the columns of the + <code class="command">VALUES</code> result as <code class="literal">column1</code>, <code class="literal">column2</code>, + etc. For more details see + <a class="xref" href="sql-select.html#SQL-ORDERBY" title="ORDER BY Clause">ORDER BY Clause</a> + in the <a class="xref" href="sql-select.html" title="SELECT"><span class="refentrytitle">SELECT</span></a> documentation. + </p></dd><dt><span class="term"><em class="replaceable"><code>operator</code></em></span></dt><dd><p> + A sorting operator. For details see + <a class="xref" href="sql-select.html#SQL-ORDERBY" title="ORDER BY Clause">ORDER BY Clause</a> + in the <a class="xref" href="sql-select.html" title="SELECT"><span class="refentrytitle">SELECT</span></a> documentation. + </p></dd><dt><span class="term"><em class="replaceable"><code>count</code></em></span></dt><dd><p> + The maximum number of rows to return. For details see + <a class="xref" href="sql-select.html#SQL-LIMIT" title="LIMIT Clause">LIMIT Clause</a> + in the <a class="xref" href="sql-select.html" title="SELECT"><span class="refentrytitle">SELECT</span></a> documentation. + </p></dd><dt><span class="term"><em class="replaceable"><code>start</code></em></span></dt><dd><p> + The number of rows to skip before starting to return rows. + For details see <a class="xref" href="sql-select.html#SQL-LIMIT" title="LIMIT Clause">LIMIT Clause</a> + in the <a class="xref" href="sql-select.html" title="SELECT"><span class="refentrytitle">SELECT</span></a> documentation. + </p></dd></dl></div></div><div class="refsect1" id="id-1.9.3.185.7"><h2>Notes</h2><p> + <code class="command">VALUES</code> lists with very large numbers of rows should be avoided, + as you might encounter out-of-memory failures or poor performance. + <code class="command">VALUES</code> appearing within <code class="command">INSERT</code> is a special case + (because the desired column types are known from the <code class="command">INSERT</code>'s + target table, and need not be inferred by scanning the <code class="command">VALUES</code> + list), so it can handle larger lists than are practical in other contexts. + </p></div><div class="refsect1" id="id-1.9.3.185.8"><h2>Examples</h2><p> + A bare <code class="command">VALUES</code> command: + +</p><pre class="programlisting"> +VALUES (1, 'one'), (2, 'two'), (3, 'three'); +</pre><p> + + This 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> + + </p><p> + More usually, <code class="command">VALUES</code> is used within a larger SQL command. + The most common use is in <code class="command">INSERT</code>: + +</p><pre class="programlisting"> +INSERT INTO films (code, title, did, date_prod, kind) + VALUES ('T_601', 'Yojimbo', 106, '1961-06-16', 'Drama'); +</pre><p> + </p><p> + In the context of <code class="command">INSERT</code>, entries of a <code class="command">VALUES</code> list + can be <code class="literal">DEFAULT</code> to indicate that the column default + should be used here instead of specifying a value: + +</p><pre class="programlisting"> +INSERT INTO films VALUES + ('UA502', 'Bananas', 105, DEFAULT, 'Comedy', '82 minutes'), + ('T_601', 'Yojimbo', 106, DEFAULT, 'Drama', DEFAULT); +</pre><p> + </p><p> + <code class="command">VALUES</code> can also be used where a sub-<code class="command">SELECT</code> might + be written, for example in a <code class="literal">FROM</code> clause: + +</p><pre class="programlisting"> +SELECT f.* + FROM films f, (VALUES('MGM', 'Horror'), ('UA', 'Sci-Fi')) AS t (studio, kind) + WHERE f.studio = t.studio AND f.kind = t.kind; + +UPDATE employees SET salary = salary * v.increase + FROM (VALUES(1, 200000, 1.2), (2, 400000, 1.4)) AS v (depno, target, increase) + WHERE employees.depno = v.depno AND employees.sales >= v.target; +</pre><p> + + Note that an <code class="literal">AS</code> clause is required when <code class="command">VALUES</code> + is used in a <code class="literal">FROM</code> clause, just as is true for + <code class="command">SELECT</code>. It is not required that the <code class="literal">AS</code> clause + specify names for all the columns, but it's good practice to do so. + (The default column names for <code class="command">VALUES</code> are <code class="literal">column1</code>, + <code class="literal">column2</code>, etc. in <span class="productname">PostgreSQL</span>, but + these names might be different in other database systems.) + </p><p> + When <code class="command">VALUES</code> is used in <code class="command">INSERT</code>, the values are all + automatically coerced to the data type of the corresponding destination + column. When it's used in other contexts, it might be necessary to specify + the correct data type. If the entries are all quoted literal constants, + coercing the first is sufficient to determine the assumed type for all: + +</p><pre class="programlisting"> +SELECT * FROM machines +WHERE ip_address IN (VALUES('192.168.0.1'::inet), ('192.168.0.10'), ('192.168.1.43')); +</pre><div class="tip"><h3 class="title">Tip</h3><p> + For simple <code class="literal">IN</code> tests, it's better to rely on the + <a class="link" href="functions-comparisons.html#FUNCTIONS-COMPARISONS-IN-SCALAR" title="9.24.1. IN">list-of-scalars</a> + form of <code class="literal">IN</code> than to write a <code class="command">VALUES</code> + query as shown above. The list of scalars method requires less writing + and is often more efficient. + </p></div></div><div class="refsect1" id="id-1.9.3.185.9"><h2>Compatibility</h2><p><code class="command">VALUES</code> conforms to the SQL standard. + <code class="literal">LIMIT</code> and <code class="literal">OFFSET</code> are + <span class="productname">PostgreSQL</span> extensions; see also + under <a class="xref" href="sql-select.html" title="SELECT"><span class="refentrytitle">SELECT</span></a>. + </p></div><div class="refsect1" id="id-1.9.3.185.10"><h2>See Also</h2><span class="simplelist"><a class="xref" href="sql-insert.html" title="INSERT"><span class="refentrytitle">INSERT</span></a>, <a class="xref" href="sql-select.html" title="SELECT"><span class="refentrytitle">SELECT</span></a></span></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="sql-vacuum.html" title="VACUUM">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="sql-commands.html" title="SQL Commands">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="reference-client.html" title="PostgreSQL Client Applications">Next</a></td></tr><tr><td width="40%" align="left" valign="top">VACUUM </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 15.5 Documentation">Home</a></td><td width="40%" align="right" valign="top"> PostgreSQL Client Applications</td></tr></table></div></body></html>
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