Counting number of unique values in a column

[jimithing007]

I'm having a hard time finding a resolution unique to my situation here.

I am compiling a sales report and I need to determine exactly how many orders my sales people are selling. This report must contain every line item sold, and each order can contain one to many line items. So I have one tab titled "Rep Orders" that looks like this:

On my other tab called "Sales by Rep", I need a formula for the B column that looks at the Order# column above, and calculates the total of unique order numbers per each rep (named in the C column above):

Thanks in advance!

 

[jimithing007]

Sounds good. thanks for your help!

 

[Fluff]

My pleasure.