Say your lookup table is in D1:E10

=IF(A1="","",IF(ISNA(MATCH(A1,D1:D10)),"unknown",V LOOKUP(A1:D1:E10,2,0)))

HTH
--
AP

"Kath" a écrit dans le message de news:
...
I need to have one of three results show up in the cell.

I am using VLOOKUP to get my data result, but I need the cell to display
"unknown" if the requested data is not valid. However to add to that, I
need
the cell to display nothing at all if there is no data being requested.

Does anyone have any suggestions please?