One subquery
Select the customers who purchased the as many distinct product_key as the count of all product in product table    \n\t\n\tselect customer_id\n    from custome
Select the customers who purchased the as many distinct product_key as the count of all product in product table    \n\t\n\tselect customer_id\n    from customer\n    group by customer_id\n    having count(distinct product_key) = (select count(*) from product);
[]