SQL:left join和count聚合函数连接顺序

Question

有三个表，现需要字段 type， count（likes），count（comments）三个表关联条件：a.id=b.id=c.id，但是有count怎么关联都不对显示错误，求指导！！

Answer 1

你就说行不行

SELECT 
CASE WHEN A.type=1 THEN '男' 
WHEN A.type=2 THEN '女'
ELSE '其它' END
,b.likes,c.comments
FROM 表a A
JOIN (SELECT id,COUNT(1) AS likes FROM 表b WHERE type=1 GROUP BY id) B
ON A.id=B.id
JOIN (SELECT id,COUNT(1) AS comments FROM 表c WHERE type=2 GROUP BY id) c
ON A.id=C.id