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Diffstat (limited to 'doc/src/sgml/syntax.sgml')
| -rw-r--r-- | doc/src/sgml/syntax.sgml | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/doc/src/sgml/syntax.sgml b/doc/src/sgml/syntax.sgml index 16aa89f497f..ee2c5214aa9 100644 --- a/doc/src/sgml/syntax.sgml +++ b/doc/src/sgml/syntax.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/syntax.sgml,v 1.149 2010/08/04 15:27:57 tgl Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/syntax.sgml,v 1.150 2010/08/05 18:21:17 tgl Exp $ --> <chapter id="sql-syntax"> <title>SQL Syntax</title> @@ -1583,16 +1583,17 @@ SELECT array_agg(a ORDER BY b DESC) FROM table; <para> When dealing with multiple-argument aggregate functions, note that the <literal>ORDER BY</> clause goes after all the aggregate arguments. - For example, this: + For example, write this: <programlisting> SELECT string_agg(a, ',' ORDER BY a) FROM table; </programlisting> not this: <programlisting> -SELECT string_agg(a ORDER BY a, ',') FROM table; -- not what you want +SELECT string_agg(a ORDER BY a, ',') FROM table; -- incorrect </programlisting> - The latter syntax will be accepted, but <literal>','</> will be - treated as a (useless) sort key. + The latter is syntactically valid, but it represents a call of a + single-argument aggregate function with two <literal>ORDER BY</> keys + (the second one being rather useless since it's a constant). </para> <para> |