Question

I have 3 tables:

AAA with the columns:

id  |  text

BBB with the columns (aaa_id is a foreign key => id from the previous table – AAA):

id  |  text  | aaa_id

and CCC with the columns (bbb_id is a foreign key => id from the previous table – BBB):

id  |  text  | bbb_id

Now when I delete a record from the table AAA I want to delete all the records from the table BBB which are aaa_id = AAA.id and also delete all the records from the table CCC which are connected to the records I’d like to delete from BBB (so they have bbb_id equal to BBB.id of the records which are aaa_id equal to AAA.id).

I’ve tried to user inner join but I had no luck. Meanwhile, I select all the records with PHP and delete them separately.

The tables are MyISAM.

Answer 1

DELETE AAA, BBB, CCC
    FROM AAA
    LEFT JOIN BBB ON BBB.aaa_id = AAA.id
    LEFT JOIN CCC ON CCC.bbb_id = BBB.id

You could use INNER JOIN as well, if there’s always child records in each table. Or you can set up ON DELETE CASCADE in your foreign key constraints.