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Diffstat (limited to 'doc/src/sgml/typeconv.sgml')
| -rw-r--r-- | doc/src/sgml/typeconv.sgml | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/doc/src/sgml/typeconv.sgml b/doc/src/sgml/typeconv.sgml index 8900d0eb383..012e9cbe8a6 100644 --- a/doc/src/sgml/typeconv.sgml +++ b/doc/src/sgml/typeconv.sgml @@ -127,8 +127,10 @@ must appear in a single set of columns, the types of the results of each <command>SELECT</command> clause must be matched up and converted to a uniform set. Similarly, the result expressions of a <literal>CASE</literal> construct must be converted to a common type so that the <literal>CASE</literal> expression as a whole -has a known output type. The same holds for <literal>ARRAY</literal> constructs, -and for the <function>GREATEST</function> and <function>LEAST</function> functions. +has a known output type. Some other constructs, such +as <literal>ARRAY[]</literal> and the <function>GREATEST</function> +and <function>LEAST</function> functions, likewise require determination of a +common type for several subexpressions. </para> </listitem> </varlistentry> @@ -1041,9 +1043,11 @@ SQL <literal>UNION</literal> constructs must match up possibly dissimilar types to become a single result set. The resolution algorithm is applied separately to each output column of a union query. The <literal>INTERSECT</literal> and <literal>EXCEPT</literal> constructs resolve -dissimilar types in the same way as <literal>UNION</literal>. The +dissimilar types in the same way as <literal>UNION</literal>. +Some other constructs, including <literal>CASE</literal>, <literal>ARRAY</literal>, <literal>VALUES</literal>, -<function>GREATEST</function> and <function>LEAST</function> constructs use the identical +and the <function>GREATEST</function> and <function>LEAST</function> +functions, use the identical algorithm to match up their component expressions and select a result data type. </para> |