1.横纵表转换A表NameCourseGradeAlexEnglish80AlexChinese70AlexJapanese85BobEnglish75BobChinese85BobJapanese80 B表Name ...
1.横纵表转换
A表
Name | Course | Grade |
Alex | English | 80 |
Alex | Chinese | 70 |
Alex | Japanese | 85 |
Bob | English | 75 |
Bob | Chinese | 85 |
Bob | Japanese | 80 |
B表
Name | English | Chinese | Japanese |
Alex | 80 | 70 | 85 |
Bob | 75 | 85 | 80 |
Chris | 90 | 70 | 60 |
A -> B
select Name, SUM(case Course when 'English' then Grade else 0 end) as English,SUM(case Course when 'Chinese' then Grade else 0 end) as Chinese,SUM(case Course when 'Japanese' then Grade else 0 end) as Japanesefrom TranscriptAgroup by Name
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原标题:面试题整理:SQL(一)
关键词:sql
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