MySQL CASE WHEN 根据一个表的字段值不同关联查询两张不同的表【子查询】

MZPE00

于 2018-06-29 10:15:00 发布

阅读量1.9k

点赞数 1

CC 4.0 BY-SA版权

本文链接：https://blog.youkuaiyun.com/vgeekr/article/details/103127860

SELECT CASE WHEN t.name_a != ''
  THEN t.name_a
       WHEN t.name_b != ''
         THEN t.name_b
       ELSE t.user_id END
FROM
  (SELECT
     c.user_id,
     a.name_a,
     a.phone_a,
     u.name_u,
     u.phone_u
   FROM company c
     LEFT JOIN admin a ON c.id = a.company_id
     LEFT JOIN user u ON c.user_id = u.id) t