You can use an IF statement, checking for the value on column A. For
example, if your option on A is a value or nothing, you can use something
like this on columns B and C:
=IF(A1<"",VLOOKUP(...),"")

This will make the required VLOOKUP only if there is some data on column A,
leaving the cell blank otherwise.

Hope this helps,
Miguel.

"sheepdiver" wrote:

I would like to be able enter a formula once and have it applied if there is
data in a cell in that coulmn. I need to do a vlookup on sheet ABC and
return a value from column A. I then need to look for a corresponding entry
in sheet XYZ and return the matching values in column B & C.

Sheets ABC and XYZ will have 90% matches in column A but they will be an
undeterming length. There may be 20 entries or 420. Is there a way to enter
the formula in column B & C once and have the calc done whenever there is an
entry in the corresponding cell in column A?

Sheet ABC will have a list of computer names from Active Directory, sheet
XYZ will have a list from an application with matching computer name plus
version and last heartbeat.

TIA