TSQL 窗口函数

Posted 2023-03-31

【中文标题】TSQL 窗口函数

【英文标题】：TSQL Window Function

【发布时间】：2020-07-09 15:56:16

【问题描述】：

我有一个三列的表格：

Survey   QuestionName   SurveyQuestion     SurveyAnswer
1859     Satisfied?     1                  Yes
1859     Comments?      2                  Happy with outcome, thanks
1859     Phone Number?  3                  Not Answered
2000     Satisfied?     1                  No
2000     Comments?      2                  Rep was a d1ck. 
2000     Phone Number?  3                  5166569999

我想要最终得到一个看起来像这样的表格（注意：不需要 SurveyQuestion #3）

Survey   SurveyAnswer1    SurveyAnswer2     
1859     Yes              Happy with outcome, thanks
2000     No               Rep was a d1ck.                            

我只是想不出该怎么做...我尝试了几种方法，包括LEAD/LAG，但无法让它工作...我想我只需要有人来指出我正确的方向？？？？

【参考方案1】：

那是四列 ;)

您可以使用旧的聚合作为交叉表栗子：

select   Survey,
         SurveyAnswer1 = max(iif(SurveyQuestion = 1, SurveyAnswer, null)),
         SurveyAnswer2 = max(iif(SurveyQuestion = 2, SurveyAnswer, null))
from     YourTable
where    SurveyQuestion != 3
group by Survey