diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/syntax.sgml | 21 |
1 files changed, 10 insertions, 11 deletions
diff --git a/doc/src/sgml/syntax.sgml b/doc/src/sgml/syntax.sgml index 43df81e7648..8d8a1e91fc3 100644 --- a/doc/src/sgml/syntax.sgml +++ b/doc/src/sgml/syntax.sgml @@ -1709,10 +1709,10 @@ SELECT string_agg(a ORDER BY a, ',') FROM table; -- incorrect The syntax of a window function call is one of the following: <synopsis> -<replaceable>function_name</replaceable> (<optional><replaceable>expression</replaceable> <optional>, <replaceable>expression</replaceable> ... </optional></optional>) OVER ( <replaceable class="parameter">window_definition</replaceable> ) <replaceable>function_name</replaceable> (<optional><replaceable>expression</replaceable> <optional>, <replaceable>expression</replaceable> ... </optional></optional>) OVER <replaceable>window_name</replaceable> -<replaceable>function_name</replaceable> ( * ) OVER ( <replaceable class="parameter">window_definition</replaceable> ) +<replaceable>function_name</replaceable> (<optional><replaceable>expression</replaceable> <optional>, <replaceable>expression</replaceable> ... </optional></optional>) OVER ( <replaceable class="parameter">window_definition</replaceable> ) <replaceable>function_name</replaceable> ( * ) OVER <replaceable>window_name</replaceable> +<replaceable>function_name</replaceable> ( * ) OVER ( <replaceable class="parameter">window_definition</replaceable> ) </synopsis> where <replaceable class="parameter">window_definition</replaceable> has the syntax @@ -1749,15 +1749,14 @@ UNBOUNDED FOLLOWING names or numbers. <replaceable>window_name</replaceable> is a reference to a named window specification defined in the query's <literal>WINDOW</literal> clause. - Named window specifications are usually referenced with just - <literal>OVER</> <replaceable>window_name</replaceable>, but it is - also possible to write a window name inside the parentheses and then - optionally supply an ordering clause and/or frame clause (the referenced - window must lack these clauses, if they are supplied here). - This latter syntax follows the same rules as modifying an existing - window name within the <literal>WINDOW</literal> clause; see the - <xref linkend="sql-select"> reference - page for details. + Alternatively, a full <replaceable>window_definition</replaceable> can + be given within parentheses, using the same syntax as for defining a + named window in the <literal>WINDOW</literal> clause; see the + <xref linkend="sql-select"> reference page for details. It's worth + pointing out that <literal>OVER wname</> is not exactly equivalent to + <literal>OVER (wname)</>; the latter implies copying and modifying the + window definition, and will be rejected if the referenced window + specification includes a frame clause. </para> <para> |