diff --git a/doc/src/sgml/syntax.sgml b/doc/src/sgml/syntax.sgml index 90aa3b6c9b4..cca44794340 100644 --- a/doc/src/sgml/syntax.sgml +++ b/doc/src/sgml/syntax.sgml @@ -1,4 +1,4 @@ - + SQL Syntax @@ -1387,7 +1387,18 @@ $1.somecolumn (Thus, a qualified column reference is actually just a special case - of the field selection syntax.) + of the field selection syntax.) An important special case is + extracting a field from a table column that is of a composite type: + + +(compositecol).somefield +(mytable.compositecol).somefield + + + The parentheses are required here to show that + compositecol is a column name not a table name, + or that mytable is a table name not a schema name + in the second case.