Wednesday, May 28, 2008

Using DELETE to delete rows from an SQL Database - Tutorial

Using DELETE to remove a row from your SQL Database is simple. You basically tell the delete command the name of the table, and you help it find which row to delete. Let us delete "John Smith" from our database, because he is planning to move out of the country and no longer will use our website.

DELETE FROM Persons WHERE Name='John Smith', Level='Level 3'

And that will delete any John Smith that we have in our database, so long as John also has a Level 3. Be very careful to specify your full deletion requirements. You don't want to accidentally delete the wrong people, or an entire table's worth of information! 'DELETE FROM Persons' or 'DELETE * FROM Persons' would both, in most cases delete all the information in the table. It still leaves the table structure, so it is useful if you need to start with fresh people and the same types of information.

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