Analysis using two different data sets (Sales & Customer)

I have two different files:

1. Sales Data - Has information like Customer ID, Sales Date, Product Category, etc. (1 Sale per row)
2. Customer Data - Has information like Customer ID, Sign-Up Date, Referral Method, etc. (1 Customer per row)

I want to be able to find things like:

a) How many of the customers who bought a Promotional Product (that's a product category) were new (i.e. Sale Date = Sign-Up Date)
b) What are my best Referral Methods (in terms of # of Sales rather than # of customers)

All of these require cross-analysis using the Customer ID as the link, but I have no idea how to do this kind of thing. Any thoughts?

Originally Posted by alansidman

I don't know if MS Query is an option for Excel for Mac. If it is, then this is the perfect scenario for running a query. In MS Query join the two tables on the Customer ID and then in your Where Statement set it to Sale Date = Sign-Up Date. Here is a link to MS Query tutorial, but as I said, I don't know if this is available in MAC protocol.

http://www.exceluser.com/explore/msquery1_1.htm

I can't seem to get any of the versions I download to work on my mac. I don't suppose there's a way to do this within excel itself?