I'm trying to create a query to find missing values in a table.
Example table:
<PRE>
COL1 COL2
---- ----
A 1
A 2
A 3
A 4
B 1
B 3
C 2
C 4


I want my output to be:

COL1 COL2
---- ----
B 2
B 4
C 1
C 3
</PRE>
I thought I could...