Re: [PHP-DB] Select...
Hi First off, please create your own thread, do not reply to someone else's and change the subject. I'm having kind of trouble to get done this: Select data from a table, except those data already in a second table. Actually, if there is a rowid in table2, I wont get it from table1, rowid is the key that relates both tables. I just can't express this with a SQL statement!! idequipomed is the key that relates both tables!! So, if idequipomed is already in Table2, I shouldn't get it from Table1. Any suggestions? You need to do a join between the two tables using the common column to make the connection. This should get you started SELECT * FROM Table1 RIGHT JOIN Table2 USING (idequipomed) WHERE Table1.idequipomed IS NULL -- Niel Archer -- PHP Database Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DB] Select...
Original Message Subject: [PHP-DB] Select... From: Miguel Guirao [EMAIL PROTECTED] To: php-db@lists.php.net Date: 15.1.2008 4:44 Hello List, I'm having kind of trouble to get done this: Select data from a table, except those data already in a second table. Actually, if there is a rowid in table2, I wont get it from table1, rowid is the key that relates both tables. I just can't express this with a SQL statement!! idequipomed is the key that relates both tables!! So, if idequipomed is already in Table2, I shouldn't get it from Table1. Any suggestions? Many ways to do this. Choose the solution that gives you the best performance. Solution 1: SELECT t2.idequipomed FROM table2 t2 WHERE NOT EXISTS ( SELECT 1 FROM table1 WHERE table1.idequipomed = t2.idequipomed ) Solution 2: SELECT idequipomed FROM table2 WHERE idequipomed NOT IN (SELECT idequipomed FROM table1) Solution 3: SELECT table2.idequipomed FROM table2 LEFT JOIN table1 ON table1.idequipomed = table2.idequipomed WHERE table1.idequipomed IS NULL -- PHP Database Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
