Question

I have 2 tables: products & category

I’m trying to write the sql to count the number of products per category. So far I have this:

SELECT `name`, count(*) as `size`
FROM products
INNER JOIN category ON category.`id` = products.`categoryID`
GROUP BY category.`name`

This will return me a list of each category name and the number of products for that category. However it doesn’t list categories that have 0 products. How do I solve this?

Answer 1

Use a right join.

SELECT `name`, count(*) as `size`
FROM products
RIGHT JOIN category ON category.`id` = products.`categoryID`
GROUP BY category.`name`