使用左连接和内连接就可以搞定
具体SQL语句如下:
select clerk_info.id as id,hometel.tel as hometel,companytel.tel as company
from clerk_info
left join hometel on clerk_info.id=hometel.id
inner join companytel on hometel.id=companytel.id其中hometel.id和companytel.id指的是与职工表相关联的外键
具体SQL语句如下:
select clerk_info.id as id,hometel.tel as hometel,companytel.tel as company
from clerk_info
left join hometel on clerk_info.id=hometel.id
inner join companytel on hometel.id=companytel.id其中hometel.id和companytel.id指的是与职工表相关联的外键
select ci.id as id,hm.tel as hometel,cp.tel as companytel
from clerk_info ci
left join hometel hm on hm.id=ci.id
left join companytel cp on cp.id=ci.id结果:
id hometel companytel
1 12345678
2 23456789 34567890
3 45678901
这个还不对,companytel表和hometel没有直接的关联,他们都是与clerk_info有关系,写成hometel.id=companytel.id 不行吧