Hi.
I use my spreadsheet as a database containing some 15,000
transactions.
The fields include Customer No. in column 'L' and a Period field in
column 'C'. The Customer No. may be alphabetical, numeric or
alphanumeric. The period is the year. An individual customer may
have anything from 1 to 50 transactions in the database which is
sorted by Customer No. With this forums help I have successfully
counted the number of transactions by period, and totalled the value
by period.

I would now like to count the total number of different customers I
have within the database and also in a transaction period.

Can anyone help?

Regards,
Dave Moore