Finding unique combinations of data

Originally Posted by LAF

I have a spreadsheet where the users can enter data on about 500 of the line items. Some of the data is entered through pick-lists. I have 2 columns of data that is driven by pick-lists in a dialog. I want to allow only up to 10 different unique combinations of those columns within the spreadsheet. Is there a way to automatically count the different combinations and also to find the unique combinations?

One way is, in a spare column, put

=SUMPRODUCT(--(B$1:B$10=B1*(--(C$1:C$10=C1))))

where B and C denote the two columns to be tested.

Select that column and use Format, Conditional Format to highlight in red >10, and to highlight in green =1

does this help?
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Originally Posted by LAF

I tried it, but I get a #Value! error.

Can you paste here a copy of the formula that you have, and the first two rows of data.

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