DELETE FROM table_a WHERE id IN(
SELECT table_a.id AS id FROM table_a, table_b
WHERE table_a.object_id = 1 AND table_a.code = 'code'
AND table_a.code = table_b.code
AND table_b.id = table_a.b_id
AND table_b.table = 'testTable')
This is a (somewhat simplified) query I want MySQL to execute. I read on other pages of stackoverflow that this wasn't supported and that it's solvable by using JOINS. How could this be 'transcribed' to a query using JOINS? I find it hard to do so, because I've never tried creating DELETE queries with more than one table.
You can't delete from a table and reference the same table in a subquery — just a limitation of MySQL. Something like the following should work:
DELETE FROM table_a
USING table_a
INNER JOIN table_b
ON table_a.code = table_b.code
AND table_b.id = table_a.b_id
AND table_b.table = 'testTable'
WHERE table_a.object_id = 1
AND table_a.code = 'code'
The important part is USING
. If you just join the two tables, you'll delete records from both. USING
tells MySQL to use these tables for processing, but only delete from the tables in the FROM
clause.