Hello, its not error. Only SQL specific :-) NULL <> NULL
Regards Pavel Stehule On Tue, 6 Jul 2004, David Newall wrote: > PostgreSQL version: 7.4.3 (RPMs from ftp.au.postgresql.org) > > Operating Sysem: Fedora Core 1 > > CREATE TABLE t1 (i INTEGER, j INTEGER); > INSERT INTO t1 VALUES (1, NULL); > CREATE TABLE t2 AS SELECT * FROM t1; > SELECT * FROM t1 JOIN t2 USING (i, j); > i | j > ---+--- > (0 rows) > > I believe the one row, which is identically present in both table, > should be selected. The problem occurs because of the NULL value. > > > ---------------------------(end of broadcast)--------------------------- > TIP 3: if posting/reading through Usenet, please send an appropriate > subscribe-nomail command to [EMAIL PROTECTED] so that your > message can get through to the mailing list cleanly > ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org