*** pgsql.old/doc/src/sgml/func.sgml 2005-05-23 03:50:01.000000000 +0200 --- pgsql.new/doc/src/sgml/func.sgml 2005-06-01 19:17:08.000000000 +0200 *************** *** 279,284 **** --- 279,300 ---- a < x OR a > y + There is special variant of this operator BETWEEN SYMMETRIC. + In this case isn't important x <= y and + a BETWEEN SYMMETRIC x AND y + is equivalent to + + (a >= x AND a <= y) OR (a >= y AND a <= x) + + Similarly, + + a NOT BETWEEN SYMMETRIC x AND y + + is equivalent to + + (a < x OR a > y) OR (a < y OR a > x) + + There is no difference between the two respective forms apart from the CPU cycles required to rewrite the first one into the second one internally.