Count duplicates very difficult.

Count number of duplicates with two customer values AND 1 date value

Count number of duplicates with 3 customers

Count number of duplicates with 4 customers


Spreadsheet attached.

Hi
Try this formulas

Formula:

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Formula:

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Formula:

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Where F5:F11 are the Customer
See the file

Thanks Jose. Can you explain to me how those work? Thanks.

Actually, this is ok, but I don't really want a formula for each customer. I just want one formula that counts everything up. In my real data set I have 1000's of customers. Thanks.

Hi
Consider the following expression
($C$5:$C$17=$ F5)
Excel will return an array of true and false values that correspond to each of the questions C5=F5, C6=F5, C7=F5, ...C17=F5. This vector can be converted to values 0 and 1 on considering it an arithmetic operation such as the double exchange of signals. So --($C$5:$C$17=$F5) is a vector of 0 and 1 which can be operated with other same-sized vectors or with a data value.
SUMPRODUCT is one of the few functions that can work with vectors.
I hope the explanation satisfies you