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><A
NAME="QUERIES-VALUES"
>7.7. <TT
CLASS="LITERAL"
>VALUES</TT
> Lists</A
></H1
><P
> <TT
CLASS="LITERAL"
>VALUES</TT
> provides a way to generate a <SPAN
CLASS="QUOTE"
>"constant table"</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 ( <TT
CLASS="REPLACEABLE"
><I
>expression</I
></TT
> [, ...] ) [, ...]</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 <TT
CLASS="LITERAL"
>UNION</TT
>
(see <A
HREF="typeconv-union-case.html"
>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
<TT
CLASS="LITERAL"
>column1</TT
>, <TT
CLASS="LITERAL"
>column2</TT
>, etc. to the columns of a
<TT
CLASS="LITERAL"
>VALUES</TT
> 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.
</P
><P
> Syntactically, <TT
CLASS="LITERAL"
>VALUES</TT
> followed by expression lists is
treated as equivalent to:
</P><PRE
CLASS="SYNOPSIS"
>SELECT <TT
CLASS="REPLACEABLE"
><I
>select_list</I
></TT
> FROM <TT
CLASS="REPLACEABLE"
><I
>table_expression</I
></TT
></PRE
><P>
and can appear anywhere a <TT
CLASS="LITERAL"
>SELECT</TT
> can. For example, you can
use it as part of a <TT
CLASS="LITERAL"
>UNION</TT
>, or attach a
<TT
CLASS="REPLACEABLE"
><I
>sort_specification</I
></TT
> (<TT
CLASS="LITERAL"
>ORDER BY</TT
>,
<TT
CLASS="LITERAL"
>LIMIT</TT
>, and/or <TT
CLASS="LITERAL"
>OFFSET</TT
>) to it. <TT
CLASS="LITERAL"
>VALUES</TT
>
is most commonly used as the data source in an <TT
CLASS="COMMAND"
>INSERT</TT
> command,
and next most commonly as a subquery.
</P
><P
> For more information see <A
HREF="sql-values.html"
>VALUES</A
>.
</P
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