Pardon the late response, this is how I applied your suggested formula:
=IF(ISNA(MATCH($A946,'[Cost
Depr.xls]Costs'!$B$192:$N$279,0)),IF(ISNA(MATCH($A946,'[Cost
Depr.xls]Depr'!$B$74:$O$258,0)),"no match",VLOOKUP($A946,'[Cost
Depr.xls]Costs'!$B$192:$N$279,6,FALSE)),VLOOKUP($A946,'[Cost
Depr.xls]Depr'!$B$74:$N$258,6,FALSE))
I however did a little study of the MATCH formula, it appears the MATCH
formula is not what I need, ( I may be wrong)
On further search on this discussion group, I met the formula below which
actually met my need.
=IF(NOT(ISERROR(VLOOKUP($A946,'[Cost
Depr.xls]Costs'!$B$192:$N$279,5,FALSE))),VLOOKUP($A946,'[Cost
Depr.xls]Costs'!$B$192:$N$279,5,FALSE),IF(NOT(ISERROR(VLOOKUP($A946,'[Cost
Depr.xls]Depr'!$B$74:$N$258,5,FALSE))),VLOOKUP($A946,'[Cost
Depr.xls]Depr'!$B$74:$O$258,5,FALSE),"not here"))
I appreciate you all, and I am still ready to learn more.