>From 5.0.1, I get ... e c b 1 1 1 2 2 2 3 3 3 NULL NULL 4
PB ----- Original Message ----- From: Ian Sales To: [EMAIL PROTECTED] Sent: Thursday, October 07, 2004 4:21 AM Subject: Can someone please explain this? During some training on SQL recently, the following occurred. No one can explain it. The training used five tables A, B, C , D and E, each with a single int column. Table A has column a with values 1, 2, 3, 4, 5 Table B has column b with values 1, 2, 3, 4 Table C has column c with values 1, 2, 3, 4, 5, 6 Table D has column d with values 1, 2, 3, 4 Table E has column e with values 1, 2, 3 When running the following SQL... select * from E left join C on e = c right join B on e = b; we got the following results: +------+------+------+ | e | c | b | +------+------+------+ | 1 | 1 | 1 | | 2 | NULL | 1 | | 3 | NULL | 1 | | 1 | NULL | 2 | | 2 | 2 | 2 | | 3 | NULL | 2 | | 1 | NULL | 3 | | 2 | NULL | 3 | | 3 | 3 | 3 | | 1 | NULL | 4 | | 2 | NULL | 4 | | 3 | NULL | 4 | +------+------+------+ 12 rows in set (0.00 sec) Common sense expects the number of rows returned to be four. So where's the Cartesian coming from? - ian -- | Ian Sales Broadband Solutions for | | Database Administrator Home & Business | | PlusNet plc http://www.plus.net | + ----------- PlusNet - The Smarter Way to Internet ----------------+ -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
