Lookups across multiple sheets

[Mark Verboom <mark verboom net>]

Hi,

I've recently been dyving a bit deeper into working with gnumeric and
I've ran into a problem I can't seem to solve.

I've got a spreadsheet with multiple pages. Each page contains two
colums (A1:B100), where the first column is a unique number and the
second is a date. On a seperate summery page I want to be able to type
in one of the unique numbers and get the date that is next to it in one
of the other sheets to appear in a cell.

The only way I've found to do this is to make the very ugly construct
with nested if's (where A6 is the cell I type in the unique number):

=if(isna(vlookup(A6,sheet1!A11:B100,2,0)),
  if(isna(vlookup(A6,sheet2!A11:B100,2,0)),
  "Unknown",
  vlookup(A6,sheet2!A11:B100,2,0)),
 vlookup(A6,sheet1!A11:B100,2,0))

This doesn't scale very well when using 7 or 8 sheets to lookup values
and is pretty much hell to maintain :)

Does anyone know a nice way to solve this?

Thanks,

Mark
-- 
The more things change, the more they stay the same.