Complicated table question.

Hello,

I have just started a new job and i was asked to do the following. Please help me as I dont know how to do it.


System ID Client Codes ID corresponding to client codes

AA 1 DE
AAB 2 DEFA
BB 3 AA
BBCD 4 AAB
CD 5 BA
DE 6 BAI
DC 7 BBCD
BA 8 CD



Question is: There should be a function where excel picks the client codes and matches with the systems codes and returns the corresponding value to the 4th column. For eg, If the client code is DE it should scan the 1st and the 2nd column and
return the ID number 6 corresponding to client code DE. However, if there are new client codes not yet stored in the system codes then it should return no value or 0 to identify it as a new code.


Thanks very much in advance. God Bless.

Cheers,

Mithhaa