Sum If with two or more conditions

[Ruben Silva]

Hello!
I've tried to make a sum if iwth two conditions, but i am thinking wrong.
What I need is a formula to make the Following:
Columns:
A B C D
Product QTD Product QTD
If on the range A finds anything that matches with range C, then Subtract D-B

Is this possible?

Thanks In advance.

RS

 

[JE McGimpsey]

One way:

=SUMPRODUCT(--(A1:A100=C1:C100),D1100-B1:B100)