I really think you need to decide what to do under the various possibilities.
What should happen if there are 0 instances of "Cinergi", 1 occurence, more
than 1 occurence, etc. The quality of responses will be better if you
provide more details.

This would return "None" for 0 occurences, "PDB" for one instance, and
"Multiple" if it appears more than once.
=CHOOSE(MIN(COUNTIF('Purchase Day
Book'!B31:B41,"Cinergi"),2)+1,"None","PDB","Multip le")

If you want to return PDB if Cinergi appears one or more times:
=IF(COUNTIF('Purchase Day Book'!B31:B41,"Cinergi"),"PDB","")

If you want PDB returned only if "Cinergi" appears exactly once
=IF(COUNTIF('Purchase Day Book'!B31:B41,"Cinergi")=1,"PDB","")


"Gatsby" wrote:

I'm trying to enter a ref. in one sheet based on text data entered in another.
Being the Excel genius that I am, I came up with the following formula:
=IF('Purchase Day Book'!B31:B41,"Cinergi","PDB")
The result is "value" when I press enter.
I've tried to find an answer in the search, without success, but I've
enjoyed reading the other questions.
I'm wondering too, what will happen if "Cinergi" appears more than once
between
"B31:B41" in the other sheet.
Any ideas should be most welcome.
Gatsby (Not the Great)