Re: Select...
| From: | OKi98 | Date: | Tue, 15 Jan 2008 11:30:46 +0000 |
| Subject: | Re: Select... | ||
| References: | 1 | Groups: | php.db |
| Request: | Send a blank email to php-db+get-44527@lists.php.net to get a copy of this message | ||
-------- Original Message --------
Subject: [PHP-DB] Select...
From: Miguel Guirao <miguel.guirao@mail.telcel.com>
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