How to check if data in one workbook is not duplicated in another?

[Amstrad]

I have 2 workbooks. The first workbook contains master list of all customers we have ever contacted. The 2nd workbook contains a number of potential new customers that we want to contact with a promotion.

Before contacting the new potential customers, I want to check that we have never contacted them before, in which case they would be on the master list.

What can I create that will allow me to check if the cutomer ID on workbook 2 appears in the list on workbook 1 and if so, delete that customer from that sheet iand add it to a new sheet called "Already Contacted"?

Many thanks for your help.

 

[MattsDad]

This is probably not the best solution and is definitely not automated, but it can help you identify the rows to delete from your new list.

I put the master list in column A, the new list in column B and this formula in column C for each record in B:

=IF(ISNA(VLOOKUP(B2,$A:$A,1,FALSE)),"New","Existing")

You can then filter your new list data on "Existing" and delete all of those rows. What you have left is all "New" data that you can copy and paste.

Like I said, not elegant, but it will work. I'm sure someone else in this forum will have a better/faster way to do this.

 

[Amstrad]

Many thanks for that. Although it's not automated, it's certainly a great help