sql 加入时标识符无效

Question

我正在尝试学习 JOINS，但无法使它起作用。尝试将第二个 table 加入第一个以获得分区的名称，即 dname 变量。

select e.COUNT(empID), e.SUM(salary), e.DID, d.dname
from employee e
right join division on e.DID=d.DID
group by DID

Answer 1

您在 division 和组上错过了别名 d，并且别名进入了 select 行

上的函数调用

select COUNT(e.empID), SUM(e.salary), e.DID, d.dname
from employee e
right join division d on e.DID=d.DID
group by e.DID

Answer 2

select COUNT(e.empID), SUM(e.salary), e.DID, d.dname
from employee e
right join division d on e.DID=d.DID
group by e.DID, d.dname

sql invalid identifier on join