由参数决定的列名

Question

两种方法我都试过了。第一个有语法错误。第二个推送结果中的每一列，而不仅仅是与@LabelID 匹配的那一列。

    SELECT  (SELECT CASE @LabelID
         WHEN 1 THEN count(h.ee_cmn_idfr) as 'DIR'
         WHEN 2 THEN count(h.ee_cmn_idfr) as 'DD'
         WHEN 3 THEN count(h.ee_cmn_idfr) as 'OD_Staff'
         WHEN 4 THEN count(h.ee_cmn_idfr) as 'DI_BC'
         WHEN 5 THEN count(h.ee_cmn_idfr) as 'DI_PLs'
         WHEN 6 THEN count(h.ee_cmn_idfr) as 'DI_PQAs'
         WHEN 7 THEN count(h.ee_cmn_idfr) as 'DI_FTEs'
         WHEN 8 THEN count(h.ee_cmn_idfr) as 'AIPQBBC'
         WHEN 9 THEN count(h.ee_cmn_idfr) as 'AIPQB_PL'
         WHEN 10 THEN count(h.ee_cmn_idfr) as 'AIPQB_PQA'
         WHEN 11 THEN count(h.ee_cmn_idfr) as 'AIPQB_GS13S'
         WHEN 12 THEN count(h.ee_cmn_idfr) as 'AIPQB_FTE'
         WHEN 13 THEN count(h.ee_cmn_idfr) as 'IT_Staff'
         WHEN 14 THEN count(h.ee_cmn_idfr) as 'IT_Sup'
        )

第二种方法：

SELECT
 CASE WHEN @LabelID = 1 THEN count(h.ee_cmn_idfr) as 'DIR'
,CASE WHEN @LabelID = 2 THEN count(h.ee_cmn_idfr) END as 'DD'
,CASE WHEN @LabelID = 3 THEN count(h.ee_cmn_idfr) END as 'OD_Staff'
,CASE WHEN @LabelID = 4 THEN count(h.ee_cmn_idfr) END as 'DI_BC'
,CASE WHEN @LabelID = 5 THEN count(h.ee_cmn_idfr) END as 'DI_PLs'
,CASE WHEN @LabelID = 6 THEN count(h.ee_cmn_idfr) END as 'DI_PQAs'
,CASE WHEN @LabelID = 7 THEN count(h.ee_cmn_idfr) END as 'DI_FTEs'
,CASE WHEN @LabelID = 8 THEN count(h.ee_cmn_idfr) END as 'AIPQBBC'
,CASE WHEN @LabelID = 9 THEN count(h.ee_cmn_idfr) END as 'AIPQB_PL'
,CASE WHEN @LabelID = 10 THEN count(h.ee_cmn_idfr) END as 'AIPQB_PQA'
,CASE WHEN @LabelID = 11 THEN count(h.ee_cmn_idfr) END as 'AIPQB_GS13S'
,CASE WHEN @LabelID = 12 THEN count(h.ee_cmn_idfr) END as 'AIPQB_FTE'
,CASE WHEN @LabelID = 13 THEN count(h.ee_cmn_idfr) END as 'IT_Staff'
,CASE WHEN @LabelID = 14 THEN count(h.ee_cmn_idfr) END as 'IT_Sup'

Answer 1

以下是使用动态 SQL 执行此操作的方法：

样本数据：

IF OBJECT_ID('tempdb..#INPUT') IS NOT NULL
    DROP TABLE #INPUT;

CREATE TABLE #INPUT(RowID       INT IDENTITY(1, 1)
               , ee_cmn_idfr INT);

INSERT INTO       #INPUT(ee_cmn_idfr)
VALUES
      (1),
      (1),
      (1),
      (1),
      (1),
      (1),
      (1),
      (1),
      (1),
      (1),
      (1),
      (1);

SQL查询：

DECLARE @LabelID INT = 1; --<-- set the labelID 

DECLARE @SQL NVARCHAR(MAX) = ''; --<-- declare a variable to hold the dynamic sql

SELECT @SQL = 'SELECT COUNT(ee_cmn_idfr) AS '+QUOTENAME(CASE @LabelID
                                                WHEN 1 THEN 'DIR'
                                                WHEN 2 THEN 'DD'
                                                WHEN 3 THEN 'OD_Staff'
                                                WHEN 4 THEN 'DI_BC'
                                                WHEN 5 THEN 'DI_PLs'
                                                WHEN 6 THEN 'DI_PQAs'
                                                WHEN 7 THEN 'DI_FTEs'
                                                WHEN 8 THEN 'AIPQBBC'
                                                WHEN 9 THEN 'AIPQB_PL'
                                                WHEN 10 THEN 'AIPQB_PQA'
                                                WHEN 11 THEN 'AIPQB_GS13S'
                                                WHEN 12 THEN 'AIPQB_FTE'
                                                WHEN 13 THEN 'IT_Staff'
                                                WHEN 14 THEN 'IT_Sup'
                                             END)+' FROM #INPUT'; --<-- you'll have to change the name of the table accordingly 

PRINT(@SQL); --<-- print out the query not needed but nice to have for debuging 

EXEC (@SQL); --<-- execute the dynamic sql

PRINT(@SQL)

将打印以下内容：

SELECT COUNT(ee_cmn_idfr) AS [DIR] FROM #INPUT

结果：

上面的代码会选择列名如下：

• WHEN 1 THEN 'DIR'
• 当 2 然后 'DD'
• 当 3 时“OD_Staff”
• 当 4 THEN 'DI_BC'
• WHEN 5 THEN 'DI_PLs'
• 当 6 时“DI_PQAs”
• WHEN 7 THEN 'DI_FTEs'
• 8 点时“AIPQBBC”
• 9 时，然后是“AIPQB_PL”
• 当 10 时“AIPQB_PQA”
• 11 时，然后是“AIPQB_GS13S”
• 当 12 时，然后是“AIPQB_FTE”
• 13 岁时，“IT_Staff”
• 14 岁时“IT_Sup”