I wrote a script in qurey a list from two related (PK--FK) tables.
I wanted to qurey two catelogues:
1.Exist in one table as PK but not exist in the other table;
2.Exist in one table as PK and also in the other tabls as FK;
Both 1 & 2 have to satisfy condition A&B;
There exist this logical "OR" to pursue the qurey.eg.
and SSN not in
or SSN in
I wonder by doing this am I right in the logics? Is there any better solutions?