diff --git a/doc/src/sgml/xfunc.sgml b/doc/src/sgml/xfunc.sgml index 529bdec3ef9d0b5e8abc22e96bb6dfa5c1438d13..e3c36d039742d7557d7156ad88b286fa1488e282 100644 --- a/doc/src/sgml/xfunc.sgml +++ b/doc/src/sgml/xfunc.sgml @@ -1,5 +1,5 @@ <!-- -$Header: /cvsroot/pgsql/doc/src/sgml/xfunc.sgml,v 1.40 2001/10/26 21:17:03 tgl Exp $ +$Header: /cvsroot/pgsql/doc/src/sgml/xfunc.sgml,v 1.41 2001/11/01 04:07:29 tgl Exp $ --> <chapter id="xfunc"> @@ -72,10 +72,13 @@ $Header: /cvsroot/pgsql/doc/src/sgml/xfunc.sgml,v 1.40 2001/10/26 21:17:03 tgl E <para> SQL functions execute an arbitrary list of SQL statements, returning - the results of the last query in the list. In the simple (non-set) + the result of the last query in the list, which must be a + <literal>SELECT</>. + In the simple (non-set) case, the first row of the last query's result will be returned. - (Bear in mind that <quote>the first row</quote> is not well-defined - unless you use <literal>ORDER BY</>.) If the last query happens + (Bear in mind that <quote>the first row</quote> of a multi-row + result is not well-defined unless you use <literal>ORDER BY</>.) + If the last query happens to return no rows at all, NULL will be returned. </para> @@ -441,7 +444,8 @@ SELECT name, listchildren(name) FROM nodes; (5 rows) </screen> - Notice that no output row appears for Child2, Child3, etc. + In the last SELECT, + notice that no output row appears for Child2, Child3, etc. This happens because listchildren() returns an empty set for those inputs, so no output rows are generated. </para>