No suggestions so far... :o

Perhaps if I cut the problem down a little, people will be more inclined to put on their thinking caps...

So... if one has the same 2 columns as described before:

[C1] [C2]

Prod1 CharlieCo
Prod3 AlphaCorp
Prod2 BetaInc
Prod3 BetaInc
Prod1 AlphaCopr

How would one add a 3rd column, C3, that presents the full product mix purchased by each customer?

[C1] [C2] [C3]

Prod1 CharlieCo Prod1
Prod3 AlphaCorp Prod3+Prod1
Prod2 BetaInc Prod 2+Prod3
Prod3 BetaInc Prod2+Prod3
Prod1 AlphaCopr Prod3+Prod1

I could probably solve the rest of the problem if I knew how to generate this 3rd column.

Thanks and cheers!

Jay


PS: Obviously extra credit to anyone who can see a way to avoid creating new columns of interim data!