Hi Chris,

the following array formula will do what you want:

=SUM((IF(A$2:A$14=E2,1/COUNTIF(B$2:B$14,B$2:B$14),"")))

Where E2 contains the store name and column A are your stores and column B
the invoice numbers. To enter this hold down the Shift and Ctrl keys and
press Enter.

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Cheers,
Shane Devenshire


"Chris K" wrote:

I have a list of stores with many order numbers, the order numbers are
duplicated. I need to count the unique number of order numbers according to
each store without manually removing duplicates etc. within excel 2007.
e.g.
Store Order Number
apost 100124
apost dave101
apost dave101
apost 100024
fone 115
fone 1000214
fone lar1004
fone 1000214
fone 10021

Result
apost 3
fone 4

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Chris K
Excel user