查询表Employee员工表中每个部门员工平均工资的SQL语句是()。
A.
select DepartmentID,avg(Salary) from Employee group by Salary
B.
select DepartmentID,avg(Salary) from Employee order by Salary
C.
select DepartmentID,avg(Salary) from Employee group by DepartmentID
D.
select DepartmentID,avg(Salary) from Employee order by DepartmentID