I have to update a list of clients every week as per the following format:
Column A Branch Code
Column B Account Number
Column C Product Code
Column D Amount

Now, every week when I receive a new list I need to fist enter a formula in
COLUMN E in the old sheet as =+A2&"-"&B2&"-"&C2 copied in all the rows and
then workout the account-wise differences by entering the following type of
formula in the new sheet's COLUMN E for former amounts:

=+IF(ISNA(VLOOKUP(A2&"-"&B2&"-"&C2,OLDSHEET!$E$2:$E$10000,1,0)),"",SUMIF(OLDSHEE T!$E$2:$E$10000,A2&"-"&B2&"-"&C2,OLDSHEET!$D$2:$D$10000))

so as to calculate the total amount pertaining to the respective branch's
client's said product.

Any idea how to shorten such a formula and carryout a similar exercise
without creating the EXTRA COLUMN "E" in the Old Sheet, i.e. inserting
formulas like:

=+A2&"-"&B2&"-"&C2?

Thanx in advance,

Best Regards,
FARAZ A. QURESHI