(OT) MySQL: delete from multiple tables

[Anonymous Monk]

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[trammell]

Questions specific to MySQL are probably better asked on one of the MySQL mailing lists. I've had good luck on the "General Discussion" list.

[jhourcle]

The correct delimiter in SQL is single quotes.

DELETE FROM table1 WHERE data_id='111';
DELETE FROM table2 WHERE data_id='111';
DELETE FROM table3 WHERE data_id='111';

mySQL will support deletes from multiple tables, if you're using mySQL 4.0 or later, but I don't suggest it, as it can lock you into using mySQL, and it would mean that should you want to change out your backend, you'll have to go through and remove every mySQL-ism in your code. I find it better to be database-ambiguous unless it's something that you can't do efficiently without it.

Update: I stand corrected -- recent versions of mySQL supports double quotes as a delimiter. I would still advise against it, so you don't have problems should you later move to Oracle, or some other less forgiving database.

[Jasper]

Have you tried using double quotes in mySQL? I'm pretty sure it works. And I don't think you mean 'delimiter', either. You probably mean something to do with quoting. Whatever, he should be using placeholders.

(A problem I see is that he has a ';' on the end, and if you pass that in via DBI or whatever, it'll screw things up)

OK, maybe delimiter might be the right word. I've been wrong before :)

[bpphillips]

as noted above, this isn't the best place for SQL questions but here's how you would do that in recent (>= 4.0) versions of MySQL:

DELETE FROM table1, table2, table3 
USING table1 
    INNER JOIN table2 USING(data_id) 
    INNER JOIN table3 USING(data_id) 
WHERE table1.data_id = 111

Starting in MySQL 4.1 you can use table aliases (must be consistent in both the FROM and USING clauses

[Anonymous Monk]

Thanks...this works

[perl_lover]

Hi

For deleting multiple tables you need to use like this.

DELETE table1.*, table2.*,table3.* FROM table1, table2, table3 WHERE table1.data_id="111";

-perl_lover

[Anonymous Monk]

Oh, this is the error i get in mysql:

064: You have an error in your SQL syntax. Check the manual that corresponds to your MySQL server version for the right syntax to use near '* FROM hotfix, softwareinstalled WHERE data_set="temporary"' at

cheers, Steve

[jhourcle]

That's a different problem. Well, there's still the problem with the use of double quotes instead of single quotes, but I'm guessing you also tried specify the fields as *. Delete does not take a field list, as it removes all fields. If you want to use the multi-table delete (which I still don't recommend), you should use:

DELETE FROM hotfix, softwareinstalled WHERE data_set='temporary';

and not

DELETE * FROM hotfix, softwareinstalled WHERE data_set="temporary";

Update: double quotes aren't a problem in mySQL, as per Jasper