I need a forumla that will work like a sumif but I need to do a lookup to
determine the column that is summed. In the example worksheet below, on
sheet 1 cell B2, i need a formula that will sum from sheet 2 Column C for all
the 3100 references. The dates on Sheet 2 can change so the Column
refernence could change. I tried using a vlookup, with a match/indirect
forumla to return the column number, but with multiple 3100's, that formula
doesn't sum the numbers.


Sheet1
Column A ColumnB Column C Column D
Labor cat 07/01/09 08/01/09 09/01/09
3100
4200
5200

Sheet 2
Column A ColumnB Column C Column D
Labor cat 06/01/09 07/01/09 09/01/09
3100 25 72
30
4200 15 20
80
5200 50 60
3
3100 23 52
5

Any help is greatly appreciated, and if i can clarify anything just let me
know.

Thanks!