在 SQL 服务器中将行更改为列

Question

我已经处理这个查询一个半小时了，但我无法完成它，

首先，这是我的查询：

SELECT  
    Questions, PossibleAnswer, 
    ((COUNT(PossibleAnswer) + 0.0) / 10 ) * 100 AS Percentage 
FROM  
    (SELECT  
         A.AnswerID, B.Questions, B.QuestionID, C.PossibleAnswer  
     FROM 
         TblSurveyCustomerAnswers A  
     INNER JOIN 
         TblSurveyQuestion B ON A.QuestionID = B.QuestionID 
     INNER JOIN 
         TblSurveyAnswer C ON A.AnswerID = C.AnswerID 
     WHERE 
         A.CustomerID = 1) AS SOURCE  
GROUP BY 
    Questions, PossibleAnswer

结果如下：

现在，我希望将列名称 PossibleAnswer 的行转换为列，所以我进行了研究并找到了 PIVOT 命令（我需要动态，因为它是一个可能的答案字段）这是我的代码

DECLARE @DynamicPivotQuery AS NVARCHAR(MAX)
DECLARE @ColumnName AS NVARCHAR(MAX)

--Get distinct values of the PIVOT Column 
SELECT @ColumnName= ISNULL(@ColumnName + ',','') 
                    + QUOTENAME(PossibleAnswer)
FROM 
(
  SELECT DISTINCT X.* 
  FROM 
  (
    SELECT Questions,PossibleAnswer, ((COUNT(PossibleAnswer) + 0.0) / 10 ) * 100 AS Percentage 
    FROM  
       (  
          SELECT  A.AnswerID,B.Questions, B.QuestionID, C.PossibleAnswer  
          FROM TblSurveyCustomerAnswers A  
               INNER JOIN TblSurveyQuestion B  
                       ON A.QuestionID = B.QuestionID 
               INNER JOIN TblSurveyAnswer C 
                       ON A.AnswerID = C.AnswerID 
          WHERE A.CustomerID = 1 
       ) AS SOURCE  
    GROUP BY Questions, PossibleAnswer 
  ) X  
) AS B

--Prepare the PIVOT query using the dynamic 
SET @DynamicPivotQuery = 
    'SELECT Questions, ' + @ColumnName + '
     FROM TblSurveyCustomerAnswers A  
          INNER JOIN TblSurveyQuestion B  
                  ON A.QuestionID = B.QuestionID 
          PIVOT(Max(Questions) 
                FOR PossibleAnswer IN (' + @ColumnName + ')) AS PVTTable'

--Execute the Dynamic Pivot Query
EXEC sp_executesql @DynamicPivotQuery

我无法完成枢轴工作，需要帮助。我卡住了。看到这个错误：

Answer 1

一般来说，对于此类问题，您应该提供样本数据、table 定义和预期输出，以便人们可以使用您的脚本，fiddle 并生成有效的内容。请参阅 How to post a T-SQL question on a public forum 了解执行此操作的一种方法。

由于很难查看动态脚本，没有 table 结构，并指出您的问题所在，让我给您以下建议：

与其使用生成输出的大查询并围绕该大查询形成查询，不如先将该查询的输出插入临时 table。您可以通过在 SELECT 子句之后放置一个 INTO #temp_table 子句来实现。这将创建一个包含查询输出的新临时 table #temp_table。

    SELECT --your select columns
    INTO #p_in -- creates a temporary table #p_in that contains the output
    FROM --the rest of your query

根据新创建的临时文件确定数据透视列table。这样会更简洁，更容易发现错误
使用临时 table 编写您的动态 SQL（同样，它会更加简洁并且更容易发现错误）
不要忘记在执行动态SQL后DROP临时table。

Answer 2

我只是尝试在没有临时 table 的情况下解决问题。您可以根据需要编辑查询。

--For PIVOT column

DECLARE @ColumnName AS NVARCHAR(MAX)

SELECT   @ColumnName ''''+ PossibleAnswer + '''' + ' , ' + @ColumnName
FROM 
(
    SELECT  
        DISTINCT PossibleAnswer
    FROM  
    (
        SELECT  
             A.AnswerID, B.Questions, B.QuestionID, C.PossibleAnswer  
         FROM 
             TblSurveyCustomerAnswers A  
         INNER JOIN 
             TblSurveyQuestion B ON A.QuestionID = B.QuestionID 
         INNER JOIN 
             TblSurveyAnswer C ON A.AnswerID = C.AnswerID 
         WHERE 
             A.CustomerID = 1
    ) AS SOURCE  
)B

--删除最后一个逗号

 IF @ColumnName != ''
   BEGIN
       SET @ColumnName = SUBSTRING(@ColumnName, 1, LEN(@ColumnName)-1)
   END

-- 生成结果

SELECT * 
FROM
(
    SELECT Questions,PossibleAnswer, ((COUNT(PossibleAnswer) + 0.0) / 10 ) * 100 AS Percentage 
    FROM  
       (  
          SELECT  A.AnswerID,B.Questions, B.QuestionID, C.PossibleAnswer  
          FROM TblSurveyCustomerAnswers A  
               INNER JOIN TblSurveyQuestion B  
                       ON A.QuestionID = B.QuestionID 
               INNER JOIN TblSurveyAnswer C 
                       ON A.AnswerID = C.AnswerID 
          WHERE A.CustomerID = 1 
       ) AS SOURCE  
    GROUP BY Questions, PossibleAnswer 
)C
PIVOT
( Max(Questions) 
       FOR PossibleAnswer IN (@ColumnName)
) AS PVTTable

在 SQL 服务器中将行更改为列

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