Question

Here is my SQL

SELECT items.name, items.id, items.price,
COUNT(cart_items.itemId) AS quantity
FROM `cart_items`
LEFT JOIN `items`
ON cart_items.itemId = items.id
WHERE cart_items.cartId = '2'

There are no rows in the table cart_items with the cartId of 2. Yet, the resultset still shows one empty row. Why? What’s wrong with my query?

(If I set cart_items.cartId ='1' (there are rows in the table with cartId of 1) then everything returns fine.

Excuse me, I’m quite new to this kind of MySQL.

Answer 1

Because you use COUNT() (an aggregating function). You should move counting items to a subquery.