数据库实现行列转换(mysql示例)

这篇文章通过sql示例代码给大家介绍了mysql/' target='_blank'>mysql数据库如何实现行列转换，下面话不多说，直接来看示例代码吧。

原表：

表名 :user----------------------------------------name    | course  | grade----------------------------------------zhangsan  | Java   | 70----------------------------------------zhangsan  | C++   | 80----------------------------------------lisi    | java   | 90----------------------------------------lisi    | C#    | 60----------------------------------------

用一条 SQL 语句得到如下形式：

----------------------------------------name   | java | C++ | C#----------------------------------------zhangsan | 70  | 80  | null----------------------------------------lisi   | 90  | null | 60----------------------------------------

方案一

select  name,sum(case when course='java' then grade end) as java,sum(case when course='C++' then grade end) as C++,sum(case when course='C#' then grade end) as C#from test group by name

方案二

select distinct c.`name` AS name,(select grade from test where name = c.`name` and course = 'java' )as java,(select grade from test where name = c.`name` and course = 'C++' )as C++,(select grade from test where name = c.`name` and course = 'C#' )as C#from test c

总结

以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作能有一定的帮助，如果有疑问大家可以留言交流。