=IF(COUNTIF(A1:B1,"a")+COUNTIF(A1:B1,"b")=2,"yes", "no")
or
=IF(SUMPRODUCT(--(A1:B1={"a";"b"}))=2,"Yes","No")
best wishes
--
Bernard Liengme
Microsoft Excel MVP
people.stfx.ca/bliengme
email address: remove uppercase characters

"Nelson" wrote in message
...
Hi,
I facing one problem about match or look up more than two same data.
Example:

a b z
c d z
e f z
a c z
a b z

if I want the result show "Yes" or just a remark in "z" when "a" and "b"
appear two times or more. "c" and "d" , "e" and "f" , "a" and "c" show
"No"
or other remark.

I know Vlookup function is only can look up one data.
Please help me solve this problem.
Thank you