sql - 如何将行转换为 SQL 查询中具有特定内容的列？

Question

我有类似结构的数据库 - dbfiddle

结果，我想得到：

          Question1  Question2   Question3
User 1    Answer1    Answer2     Answer3
User 2    Answer1    Answer2     null
User 3    Answer1    Answer2     null
User 4    Answer1    null        null

我需要有选项来选择将要显示的问题。例如只有 1 和 3。

          Question1  Question3
User 1    Answer1    Answer3
User 2    Answer1    null
User 3    Answer1    null
User 4    Answer1    null
User 5    Answer1    Answer3

你能帮我写下这个SQL查询吗？

标签： sqlsql-server

Answer 1

SQL Server 在设计上是声明性的，不支持宏替换……这就留下了动态 SQL

示例dbFiddle

Declare @SQL varchar(max)='[question 1],[question 3]'

Select @SQL ='
select * 
 From ProcedureStepsDetails
 Pivot (max(HTMLValue) for TokenValue in ('+@SQL+') ) pvt
'
Exec(@SQL)

退货

ProcedureId question 1  question 3
User 1      answer 1    answer 3
User 2      answer 1    
User 3      answer 1    
User 4      answer 1