Delete rows where id is same as in other table

Question

Ok, here's the deal: I have following two tables in MySql-database:

**custwishes**
userid
wishid

**coursewishes**
wishid
coursename
wishmonth

"custwishes.userid" references to users-table, and custwishes.wishid is same as "coursewishes.wishid".

Now I would like to delete all records from coursewishes, where coursewishes.wishid=custwishes.wishid AND custwishes.userid=?.

I can do this with php, collecting all the necessary id's and making the delete-query in a loop for those id's, but that doesn't seem like a good idea.

I didn't even know what kind of title I should put for this question, so I hope it's not too misleading.

Any help would appreciated!

Update 07082014:13:28

I tried the "Ende Neu"'s method, but no luck. The suggestion deletes from custwishes, not from coursewishes like I would like it to do. I tried this modified version:

    DELETE
    FROM coursewishes
    WHERE coursewishes.wishid 
    IN (
      SELECT wishid 
      FROM custwishes
    )
    AND custwishes.userid = 5

This obviously results in error, because system cannot find custwishes.userid.

Perhaps there is a way to use JOIN or something alike? I'll have it a go and post what happens.

Update 11082014:12:01

Returned to the problem today, and I managed to get the cascading to work. Problem was, that I had the cascade made wrong way. :) Meaning that it cascaded from coursewishes to custwishes, not the other way around like it was supposed to.

Answer 1

You can use JOIN in DELETE statement.

If you only want to delete from coursewishes, use this statement

DELETE coursewishes
FROM coursewishes
JOIN custwishes ON coursewishes.wishid = custwishes.wishid 
WHERE custwishes.userid = 5;

If you want to delete from both tables, use

DELETE coursewishes, custwishes
FROM coursewishes
JOIN custwishes ON coursewishes.wishid = custwishes.wishid 
WHERE custwishes.userid = 5;

ON DELETE cascade works in one direction only.