案例中的排序和不同类型

Question

我需要根据对参数的Integer输入来按列排序结果集.

问题是,我需要为OrderBy使用CASE,似乎代码接受case列中的第一个'TYPE'...任何其他类型都失败.

我的代码是这样的:

    WITH error_table AS  
 (  
  SELECT Row_Number() OVER   
   (ORDER BY  
        CASE @orderBy
            WHEN 1 THEN received_date  -- Last Rx'd message  
            WHEN 2 THEN message_id -- Message Id  
            WHEN 3 THEN zibmat.short_name -- Message action type  
            WHEN 4 THEN error_action.short_name -- Status type  
            WHEN 5 THEN ime.[allocated_date] -- Allocated Date  
            ELSE received_date
    END) AS RowNumber   

   ,ime.[ijis_message_error_id]  
      ,ime.[message_id]  
      ,ime.[message_version] 

因此,当OrderBy为1时,它可以工作.它按rx_date进行排序...但是当我发送它2时,它会因数据时间转换错误而失败.

看起来所有类型都必须相同......

发送5个工作正常,因为这也是一个约会时间.

有没有办法解决这个问题？

Answer 1

CASE语句必须仅解析为一种数据类型.这与您知道@orderby将只选择一个分支并且它将是特定数据类型无关.

你可以使用这样的东西,这将是笨重但会起作用.

ORDER BY
CASE @orderBy WHEN 1 THEN received_date -- Last Rx'd message
WHEN 2 THEN 0
WHEN 3 THEN 0
WHEN 4 THEN 0
WHEN 5 THEN ime.[allocated_date] -- Allocated Date
ELSE received_date END,
CASE @orderBy WHEN 1 THEN 0
WHEN 2 THEN message_id -- Message Id
WHEN 3 THEN 0
WHEN 4 THEN 0
WHEN 5 THEN 0
ELSE 0 END,
CASE @orderBy WHEN 1 THEN ''
WHEN 2 THEN ''
WHEN 3 THEN zibmat.short_name -- Message action type
WHEN 4 THEN error_action.short_name -- Status type
WHEN 5 THEN ''
ELSE '' END

Answer 2

这似乎也有效.

ORDER BY  
        CASE @orderBy
            WHEN 1 THEN CAST(received_date AS SQL_VARIANT)  -- Last Rx'd message  
            WHEN 2 THEN message_id -- Message Id  
            WHEN 3 THEN zibmat.short_name -- Message action type  
            WHEN 4 THEN error_action.short_name -- Status type  
            WHEN 5 THEN ime.[allocated_date] -- Allocated Date  
            ELSE received_date
    END

测试用例(int,string,date)

DECLARE @P INT = Datepart(SECOND, Getdate())%3;

SELECT 'Sorting By ' + CASE @P
            WHEN 1 THEN 'modify_date'
            WHEN 2 THEN 'object_id'
            ELSE 'name'
          END  

SELECT object_id,
       name,
       modify_date
FROM   sys.objects
ORDER  BY CASE @P
            WHEN 1 THEN CAST(modify_date AS SQL_VARIANT)
            WHEN 2 THEN object_id
            ELSE name
          END