Comparing result set values of 2 queries ?

Any assistance would be so helpful !!

We have 2 tables.. lets call them INV and COST

Table INV and COST have 3 related columns, namely ID,AMOUNT and VAT. As shown below...

ID | AMOUNT | VAT ( INV TABLE )
1 |20.125 |2.896
2 |10.524 |1.425

ID | AMOUNT | VAT ( COST TABLE )
1 |20.125 |4.821 ... different to ID 1 in INV Table
2 |10.524 |1.425

If you look above, I need to sum the AMOUNT and VAT columns and get a value for each ID, then compare the two tables and get the ID's that have different values...in this case I would need a result saying ID1 as the total of INV TABLE ID1 (23.021) is different to the corresponding ID1 row in COST TABLE (24.946)

Thats it ?

Please could someone out there offer some ideas ?

THANKS

JONI'd use:SELECT *
FROM inv
JOIN cost
ON (cost.id = inv.id)
WHERE inv.amount <> cost.amount
OR inv.vat <> cost.vat-PatP