Hope someone could help me in revising a long running query. Here is the query
select * from table1 where classid is null and productid not in ( select productid from table1 where classid = 67)
In here table1 could have several occurance of productid in which productid could have different classid. The possible values of classid are: NULL,1,2,3,67. Basically I am looking for all records whose classid is null but should never had an instance in table1 where its classid is 67.
Do you have something like a "join" statment that will only include all records in the left table that is not in the right table?
Hope someone could help me with this. Thanks in advance.