ORDER BY CASE与子查询

Question

当我使用AVG或COUNT与SQL Server时，通过动态值进行排序时遇到问题。我怎样才能使它工作？

ALTER PROCEDURE GetEmployee 
@SortOrder INT 
AS 

SELECT   name, 
       AVG(salary) AS avgSalary,    
       COUNT(employeeID) AS employeeCount    

FROM   employee 

ORDER BY CASE WHEN @SortOrder = 1 THEN avgSalary 
       WHEN @SortOrder = 2 THEN employeeCount 
       ELSE name 
     END 

Answer 1

这可能会工作，基本上是一个事实，即在CASE声明所有表达式应该是强迫，能够在同一时间快速解决方法。

ALTER PROCEDURE GetEmployee 
@SortOrder INT 
AS 

SELECT   name, 
       AVG(salary) AS avgSalary,    
       COUNT(employeeID) AS employeeCount    

FROM   employee 

ORDER BY CASE WHEN @SortOrder = 1 THEN AVG(salary) END, 
     CASE WHEN @SortOrder = 2 THEN COUNT(employeeID) END, 
     CASE WHEN @SortOrder NOT IN (1, 2) THEN name END