This advanced SQL exercise is part of the book: Advanced SQL – Practical Techniques and Use-Cases, which includes 100 day-to-day SQL challenges (and solutions), need-to-know advanced features, and key concepts.
Given a Categories and Suppliers table. This table contains an indication of the various categories each supplier markets. For example, supplier no. 1 markets alcohol, tea, and coffee products.
CREATE TABLE products_and_suppliers (productID int identity(1,1), categoryName varchar(50), supplier1 int, supplier2 int, supplier3 int, supplier4 int)