SQL to join one table to another table multiple times? (Mapping products to categories)

Question

Let\'s say I have a Product, Category, and Product_To_Category table. A Product can be in multiple categories.

    Product             


        

Answer 1

I don't know what RDBMS you're using, but in MySQL you can use GROUP_CONCAT:

SELECT
  p.name,
  GROUP_CONCAT(c.name SEPARATOR ', ') AS categories
FROM
  product p
  JOIN product_to_category pc ON p.id = pc.product_id
  JOIN category c ON c.id = pc.category_id
GROUP BY
  p.name
ORDER BY
  p.name,
  c.name