Table values comparison

Question

Hi,
I am trying to write a comparison of two sets of data I imported to my database.
The data is like so:
Table1
Column1 Column2
A1 123
A1 456
B1 999
C1          895
D1 676
D1 655
D1 702
Table2
Column1 Column2
A1 456
B1 999
C1          895
D1 676
D1 655
The query below is what I thought would do the trick but it is pulling way too much data
Select * from table1, table2 where
table1.column1=table2.column1 and
table1.column2 <> table2.column2
The data results would be
TABLE1 Results: A1 123
Table2 Results: D1 702
The data in the results would be what was identified as not being in the database which is what I am trying to identify.
Help!
Thanks

Answer 1

Hi,
Careful: the order of MINUS and UNION operations is significant.
Ifthe last set operation is
MINUS
SELECT * FROM TABLE1that means noting from table1 will be in the result set, regardless of whther it was a duplicate or not. Try it.
This works better:
     SELECT     'TABLE1 Results' AS label, column1, column2     FROM     table1
UNION     SELECT     'TABLE2 Results' AS label, column1, column2     FROM     table2
MINUS     SELECT     'TABLE2 Results' AS label, column1, column2     FROM     table1
MINUS     SELECT     'TABLE1 Results' AS label, column1, column2     FROM     table2
;This is analagous to saying A + C - B - D instead of (A - B) + (C - D) if you can't use parentheses.