mysql语句用法

mysql基本用法

常用的mysql语句
left join 返回左表中所有记录和右表中连接字段相等的记录(左连接)

select r.id,d.dwname,names
from zn_kq_record3 r
left join zn_dt_staff s on r.uuid = s.uuid
left join upms_user u on s.user_username = u.username
left join zn_org d on s.unitId = d.dwcode
order by unitId,salaryNum,signDate

Case when 函数只返回第一个符合条件的值，剩下的Case部分将会被自动忽略。

case
when sex = ‘1’ then ‘男’
when sex = ‘2’ then ‘女’
else ‘未知’ end