O’Reilly Network: AboutSQL: DELETE Tips and Tricks

“It’s probably too easy to use the DELETE statement, thanks
to the (fairly) consistent syntax of the SQL standard, but I think
it’s important to provide you with as much information as
— so here goes:

DELETE FROM table_name WHERE criteria

Now that you’ve seen it, I want to warn you in loud and
unambiguous language to be EXTREMELY careful when you use it. There
is no undo. And if you forget the WHERE clause or make a mistake in
it, you run the risk of removing the entire table from the

“Just like the UPDATE command, I heartily recommend trying a
SELECT statement using the WHERE clause before you do a DELETE,
just to make sure it works like you expect it to. And you should be
exceptionally careful how you let users interface with the DELETE
command because:

SQL Wisdom #2) If users CAN delete data, they WILL
delete it … accidentally and at the worst possible time.”


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