diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 0b62e0c828..b94827674c 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -22127,7 +22127,7 @@ WHERE EXISTS (SELECT 1 FROM tab2 WHERE col2 = tab1.col2); The right-hand side is a parenthesized list - of scalar expressions. The result is true if the left-hand expression's + of expressions. The result is true if the left-hand expression's result is equal to any of the right-hand expressions. This is a shorthand notation for @@ -22158,7 +22158,7 @@ OR The right-hand side is a parenthesized list - of scalar expressions. The result is true if the left-hand expression's + of expressions. The result is true if the left-hand expression's result is unequal to all of the right-hand expressions. This is a shorthand notation for @@ -22269,26 +22269,24 @@ AND Each side is a row constructor, as described in . - The two row values must have the same number of fields. - Each side is evaluated and they are compared row-wise. Row constructor - comparisons are allowed when the operator is + The two row constructors must have the same number of fields. + The given operator is applied to each pair + of corresponding fields. (Since the fields could be of different + types, this means that a different specific operator could be selected + for each pair.) + All the selected operators must be members of some B-tree operator + class, or be the negator of an = member of a B-tree + operator class, meaning that row constructor comparison is only + possible when the operator is =, <>, <, <=, - > or - >=. - Every row element must be of a type which has a default B-tree operator - class or the attempted comparison may generate an error. + >, or + >=, + or has semantics similar to one of these. - - - Errors related to the number or types of elements might not occur if - the comparison is resolved using earlier columns. - - - The = and <> cases work slightly differently from the others. Two rows are considered @@ -22309,19 +22307,6 @@ AND considered. - - - Prior to PostgreSQL 8.2, the - <, <=, > and >= - cases were not handled per SQL specification. A comparison like - ROW(a,b) < ROW(c,d) - was implemented as - a < c AND b < d - whereas the correct behavior is equivalent to - a < c OR (a = c AND b < d). - - - row_constructor IS DISTINCT FROM row_constructor