SELECT EmpID,EmpSalaryGrade,EmpGrade
FROM Employee
ORDER BY EmpGrade,EmpSalaryGrade
与
SELECT EmpID,EmpSalaryGrade,EmpGrade
FROM Employee
ORDER BY EmpGrade+EmpSalaryGrade中
ORDER BY EmpGrade+EmpSalaryGrade 与 ORDER BY EmpGrade,EmpSalaryGrade
的区别是什么?
FROM Employee
ORDER BY EmpGrade,EmpSalaryGrade
与
SELECT EmpID,EmpSalaryGrade,EmpGrade
FROM Employee
ORDER BY EmpGrade+EmpSalaryGrade中
ORDER BY EmpGrade+EmpSalaryGrade 与 ORDER BY EmpGrade,EmpSalaryGrade
的区别是什么?
按照两者的和进行排序ORDER BY EmpGrade,EmpSalaryGrade
先按照EmpGrade排序,如果EmpGrade字段相同,再按照EmpSalaryGrade排序。
--> 测试数据:@Employee
declare @Employee table(EmpID int,EmpSalaryGrade int,EmpGrade int)
insert @Employee
select 1,2,4 union all
select 2,2,3 union all
select 3,1,8 union all
select 4,4,4 union all
select 5,3,1 union all
select 6,1,2SELECT EmpID,EmpGrade,EmpSalaryGrade
FROM @Employee
ORDER BY EmpGrade+EmpSalaryGrade
/*
EmpID EmpGrade EmpSalaryGrade
----------- ----------- --------------
6 2 1
5 1 3
2 3 2
1 4 2
4 4 4
3 8 1
*/SELECT EmpID,EmpGrade,EmpSalaryGrade
FROM @Employee
ORDER BY EmpGrade,EmpSalaryGrade
/*
EmpID EmpGrade EmpSalaryGrade
----------- ----------- --------------
5 1 3
6 2 1
2 3 2
1 4 2
4 4 4
3 8 1
*/
你可以写个查询比较一下区别ORDER BY EmpGrade+EmpSalaryGrade
按照两者的和进行排序ORDER BY EmpGrade,EmpSalaryGrade
先按照EmpGrade排序,如果EmpGrade字段相同,再按照EmpSalaryGrade排序。