Data Validation: Uniique values based on two cells

[Saighead]

Hi,

Could you help me with a case-sensitive formula that would prevent duplicate values based on two cells? Now I'm using this for column C:
=SUMPRODUCT((--EXACT($C$1:$C$100000,C1)))<2

I need the same kind of thing, only it should evaluate column B as well. So, for example,

Column B　　　　　　　　　Column C
CEO　　　　　　　　　　　　　 John Doe
engineer　　　　　　　　　　 John Doe
programmer　　　　　　　　John Doe

should be evaluated as unique values.

Thanks in advance.

Also posted here.

[JeteMc]

For a general solution, my feeling is that you could produce a concatenated 'Helper' column and apply your formula to that.
For more specific help please upload a sample by clicking on the GO ADVANCED button below the Quick Reply window and then scrolling down to Manage Attachments to open the upload window.
Let us know if you have any questions.