Hi all,

I am trying to figure the LOOKUP functions that exist in Excel, but I must
be very dumb, because I can not make it work as I want.

This is my scenario:

In one Worksheet (sheet1) it looks like this:
Column A: UserID
Column B: Firstname
Column C: Lastname
Column D: email

In the other Worksheet (sheet2) it looks like this:
Column A: Name (firtsname + lastname)
Column B. email

Here is what I want to achieve:
I Sheet2, I want under Column C a LOOKUP function that will do the follwoing:
Take the value from Sheet2!Column B, search in Sheet1!Column D and if there
is a MATCH, copy from that ROW, Column A (the UserID). If there is not match
at all, searching through the "array", it should just state "No UserID".

How on heavens Earth do I get this going?

Thank you all in advance that will take your knowledge, skills and time to
provide me with a solution and answer.

--Andreas