报错Unknown column 'u.u_id' in 'where clause'

Question

我的sql语句是：
SELECT COUNT(*) FROM wujiuser u WHERE
(SELECT MAX(days) FROM
(SELECT
@con :=(CASE WHEN ( dd = 0 OR dd = @con) THEN (@con + 1)ELSE 0 END) AS days,
dd FROM
(SELECT DATEDIFF(NOW(),t.logintime) AS dd FROM login_record t WHERE t.u_id=u.u_id ORDER BY t.logintime DESC) AS vv GROUP BY dd) AS v1)>=3

出现报错信息：Unknown column 'u.u_id' in 'where clause'

Answer 1

可能他先执行where里面的子查询的时候还没有u这个别名，你试下把u直接改成表名呢？不用要别名