mysql子查詢
阿新 • • 發佈:2018-03-08
body 所有 lar sele sel 多列 多行 相關子查詢 單列
子查詢分類
標量子查詢:查詢結果為單行單列
列子查詢:一列多行
行子查詢:多列單行
表子查詢:多行多列
子查詢支持規則
select 標量子查詢
from 【join】表子查詢
where【having】標量子查詢、行子查詢、列子查詢
exists 表子查詢
例子
select * from user where department_id =(select department_id from user where id=3)
select * from user where department_id in (select department_id from department where department like ‘A%’)
any(子查詢),至少一個滿足就可以 all(子查詢)所有都滿足 一般any跟all可以用其他子查詢代替
select * from user where salary >any(select salary from user where id in (1,2,3))
select * from user where salary >all(select salary from user where id in (1,2,3))
相關子查詢
select exists (select user_id from user where department_id=3) 結果為0或是1
常用實例 select department_name from department d where exists(select * from u where u.department_id=d.department_id ) #查詢出有員工的部門名稱
mysql子查詢