Question

I have two tables A and B. I would like to delete all the records from table A that are returned in the following query:

SELECT A.* FROM A , B WHERE A.id = B.a_id AND     b.date < '2008-10-10' 

I have tried:

DELETE A  WHERE id in (     SELECT a_id      FROM B      WHERE date < '2008-10-10') 

but that only works if the inner select actually returns a value (not if the result set is empty)

NB: this has to work on both SQLServer AND MySQL

EDIT: More information

The above delete works 100% on SQLServer

When running it on MySQL I get an ‘error in you SQL syntax’ message which points to the start of the SELECT as the problem. if I substitute the inner select with (1,2) then it works.

@Kibbee You are right it actually makes no difference if the inner select returns rows or not.

@Fred I get a ‘not unique table.alias: a’ message

Answer 1

I think this should work (works on MySQL anyway):

DELETE a.* FROM A a JOIN B b ON b.id = a.id WHERE b.date < '2008-10-10'; 

Without aliases:

DELETE A.* FROM A JOIN B ON B.id = A.id WHERE B.date < '2008-10-10';