Hi Tom, this seems a serious bug:
testdb=> testdb=> create table t1(a int, b text); CREATE TABLE testdb=> create table t2(a int, b text); CREATE TABLE testdb=> insert into t1 values(1,'pippo'); INSERT 7591667 1 testdb=> insert into t1 values(2,'pluto'); INSERT 7591668 1 testdb=> insert into t2 values(3,'paperino'); INSERT 7591669 1 testdb=> insert into t2 values(3,'paperino'); INSERT 7591670 1 select a,b from t1 union (select a,b from t2); a | b ---+---------- 1 | pippo 2 | pluto 3 | paperino (3 rows) Wrong ! The query should return 4 rows. In other words i don't know why postgres performs the following query: select a,b from t1 union (select DISTINCT a,b from t2); instead of the required one. I think i's a bug. Thank you. Silvio Scarpati ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]