When you delete rows from table A, no deletions will occur in table B unless you have specifically created, in table B, a foreign key with the ON DELETE CASCADE property, that references the primary key of A.
Assuming you haven't done that, the following query will delete matched rows from table A:
delete from tableA where exists ( select 1 from tableB where email = tableA.email )
This should work in all databases.
Some databases have their own specific DELETE syntax. In Microsoft SQL Server, for example, you could also say:
delete tableA from tableA inner join tableB on tableA.email = tableB.email
This accomplishes the same result; rows are deleted from table A only.
This was first published in January 2005