Sql 文本透视表

我所做的是基于以下回应：

我有一张像这样的桌子

InterviewID | QuestionNumber | PerformanceRatingComments
      1     |       1        |      Text1
      1     |       2        |      Text2
      2     |       1        |      Text3
      2     |       2        |      Text4
      2     |       3        |      Text3
      2     |       4        |      Text4

我想看到的是一张显示

InterviewID | Q1PerfComments | Q2PerfComments | Q3PerfComments | Q4PerfComments.  

我试过这个：

Select InterviewID, 
  pt.[1] as Q1PerfComments, 
  pt.[2] as Q2PerfComments, 
  pt.[3] as Q3PerfComments,
  pt.[4] as Q4PerfComments 
FROM 
(
    select InterviewID, QuestionNumber, PerformanceRatingComments
    from myTable
    WHERE
    PerformanceRatingComments IS NOT NULL
    and QuestionNumber >=1 
    And QuestionNumber <=4
 ) As Temp
PIVOT
(
   max(PerformanceRatingComments)
    FOR QuestionNumber In([1], [2], [3], [4])
) As pt

我收到一个错误，上面写着：

操作数数据类型文本对于max运算符无效

---

我错过了什么

根据错误消息：

操作数数据类型文本对于max运算符无效

不能将聚合函数应用于文本数据类型。我的建议是在透视数据之前将PerformanceRatingComments转换为varcharmax：

Select InterviewID, 
  pt.[1] as Q1PerfComments, 
  pt.[2] as Q2PerfComments, 
  pt.[3] as Q3PerfComments,
  pt.[4] as Q4PerfComments 
FROM 
(
    select InterviewID, QuestionNumber, 
      cast(PerformanceRatingComments as varchar(max)) PerformanceRatingComments
    from myTable
    WHERE PerformanceRatingComments IS NOT NULL
      and QuestionNumber >=1 
      And QuestionNumber <=4
 ) As Temp
PIVOT
(
   max(PerformanceRatingComments)
    FOR QuestionNumber In([1], [2], [3], [4])
) As pt;

看