一对多关系查询

Question

I have the following query:

this->getDoctrine()->getManager();
        $sql = "SELECT shop.*
                FROM instagram_shop shop
                LEFT JOIN instagram_shop_picture picture 
                ON picture.shop_id = shop.id
                WHERE COUNT(picture) = 0
                AND shop.isLocked = 0
                AND shop.expirydate IS NOT NULL 
                AND shop.expirydate > now()
                AND shop.deletedAt IS NULL
                "

Wanted to get all shops that has 0 pictures in it. But this returns a sql error of:

General error: 1111 Invalid use of group function

Why is this?

Answer 1

SELECT shop.id
FROM instagram_shop shop
LEFT JOIN instagram_shop_picture picture ON picture.shop_id = shop.id
WHERE shop.isLocked = 0
AND shop.expirydate IS NOT NULL 
AND shop.expirydate > now()
AND shop.deletedAt IS NULL
GROUP BY shop.id
HAVING COUNT(picture.shop_id) = 0

Answer 2

You can do what you want without a group by or count() . Just find the places where the left join fails:

SELECT shop.*
FROM instagram_shop shop LEFT JOIN
     instagram_shop_picture picture 
     ON picture.shop_id = shop.id
WHERE picture.shop_id is NULL AND
      shop.isLocked = 0 AND
      shop.expirydate IS NOT NULL AND
      shop.expirydate > now() AND
      shop.deletedAt IS NULL

Answer 3

Not knowing the schema I would guess you are missing

GROUP BY shop.id

at then end of the query.

Also with having

HAVING COUNT(picture) = 0