Question

So I have a table that has a FK to a UserId, and a FK to a ProductId.

Each UserId can be listed multiple times if they have multiple products.

I need to query to get each UserId that has, for example, ProductId 1, but NOT ProductId 2.

How can I get started writing a query like this?

Edit:

But here is the part I’m having problems with; all users who have Product 1 should have Product 2, but some don’t, so I need to get the users who have Product 1 and NOT Product 2

Answer 1

select distinct userID from yourtable t
where t.ProductId=@ProductID1
and not exists(select UserID from yourtable 
                      where Userid=t.userID and ProductID=@ProductID2)