mysql - MySQL使用子查询中的表字段作为条件

Question

经过大量搜索后，我得出以下 sql 语句：

SELECT a.*, b.name as producer ,
    (SELECT ROUND(AVG(average)) 
    FROM `abc123_pb_carexperience` d 
    LEFT JOIN `abc123_pb_cars` e on d.car_id=e.id HAVING name LIKE '%a.name%') as avgrating
FROM abc123_pb_brands a
LEFT JOIN abc123_pb_producer as b on a.producer_id = b.id
ORDER BY a.name ASC

兴趣点是子查询中的条件 HAVING name LIKE。如果我将名称写为字符串（HAVING name LIKE '%bmw%'），它可以工作，但我必须使用表 a 的名称字段来获取特定品牌的所有平均评级。有没有办法做到这一点？谢谢。

Answer 1

我认为您的内部子查询应如下所示：

  (SELECT ROUND(AVG(average)) 
    FROM `abc123_pb_carexperience` d 
    LEFT JOIN `abc123_pb_cars` e on d.car_id=e.id 
    WHERE name LIKE CONCAT('%',a.name,'%'))

Answer 2

您可以像这样更改您的查询

SELECT
  a.*,
  b.name as producer,
  ROUND(AVG(d.average)) as avgrating
FROM abc123_pb_brands a
  LEFT JOIN abc123_pb_producer as b
    on a.producer_id = b.id
  LEFT JOIN `abc123_pb_carexperience` d
    ON d.name LIKE '%a.name%'
  LEFT JOIN `abc123_pb_cars` e
    on d.car_id = e.id
ORDER BY a.name ASC