sql 语句写的行列转换

Posted 2020-08-04 jkq

  以前面试老遇到一个行列转换的问题，今天没事，顺便记录一下

假设有这样一张表，如下图，创建表就不说了，直接建或者SQL语句都行 

sql语句如下

--第一种
select name as 姓名,
max(case Subject when \'语文\' then Result else 0 end) as 语文,
max(case Subject when \'数学\' then result else 0 end) as 数学,
max(case Subject when \'英语\' then Result else 0 end) as 英语,
max(case Subject when \'政治\' then Result else 0 end) as 政治,
max(case Subject when \'物理\' then Result else 0 end) as 物理
from cj group by Name

--第二种
select Subject as 科目,
MAX(case Name when \'张三\' then Result else 0 end) as 张三,
MAX(case Name when \'李四\' then Result else 0 end) as 李四,
MAX(case Name when \'王五\' then Result else 0 end) as 王五
from cj group by Subject	

　　运行结果如下