Question

I thought this would be a straightforward query to write, but it’s proving to be much trickier to achieve than I first thought.

Any help would be much appreciated – it’s driving me up the wall 🙂

I have two tables, one USERS the second; PURCHASED PRODUCTS. A user can have multiple products in the PRODUCTS table.

I have a joined query where I return a list of users that have a specific product – so far so good.

Now here’s the problem:

I want to exclude USERS that have another specific product.

Therefore, only return users that have product 1001, NOT users that have both products 1001 AND 1002 in the PRODUCTS table.

Answer 1

A slightly different approach:

SELECT u.user_id
FROM users u
JOIN purchased_products p
  ON u.user_id = p.user_id AND 
     p.product_id in (1001, 1002)
GROUP BY u.user_id
HAVING COUNT(DISTINCT p.product_id) = 1 AND
       MIN(p.product_id) = 1001