diff options
Diffstat (limited to 'doc/src/sgml/func.sgml')
| -rw-r--r-- | doc/src/sgml/func.sgml | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 35c7f75eab2..e9dbcb9f8a0 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -1394,7 +1394,8 @@ </entry> <entry><type>text</type></entry> <entry> - Concatenate all arguments. NULL arguments are ignored. + Concatenate the text representations of all the arguments. + NULL arguments are ignored. </entry> <entry><literal>concat('abcde', 2, NULL, 22)</literal></entry> <entry><literal>abcde222</literal></entry> @@ -1411,8 +1412,8 @@ </entry> <entry><type>text</type></entry> <entry> - Concatenate all but first arguments with separators. The first - parameter is used as a separator. NULL arguments are ignored. + Concatenate all but the first argument with separators. The first + argument is used as the separator string. NULL arguments are ignored. </entry> <entry><literal>concat_ws(',', 'abcde', 2, NULL, 22)</literal></entry> <entry><literal>abcde,2,22</literal></entry> @@ -1522,8 +1523,9 @@ </entry> <entry><type>text</type></entry> <entry> - Format a string. This function is similar to the C function - <function>sprintf</>; but only the following conversion specifications + Format arguments according to a format string. + This function is similar to the C function + <function>sprintf</>, but only the following conversion specifications are recognized: <literal>%s</literal> interpolates the corresponding argument as a string; <literal>%I</literal> escapes its argument as an SQL identifier; <literal>%L</literal> escapes its argument as an @@ -2034,6 +2036,18 @@ </table> <para> + The <function>concat</function>, <function>concat_ws</function> and + <function>format</function> functions are variadic, so it is possible to + pass the values to be concatenated or formatted as an array marked with + the <literal>VARIADIC</literal> keyword (see <xref + linkend="xfunc-sql-variadic-functions">). The array's elements are + treated as if they were separate ordinary arguments to the function. + If the variadic array argument is NULL, <function>concat</function> + and <function>concat_ws</function> return NULL, but + <function>format</function> treats a NULL as a zero-element array. + </para> + + <para> See also the aggregate function <function>string_agg</function> in <xref linkend="functions-aggregate">. </para> |