mysql如何实现行转列

本教程操作环境：windows7系统、mysql8.0.22版，该方法适用于所有品牌电脑。

mysql实现行转列的方法：

1、用cross join的方式实现

select * from 
(select sum(a.kills) '孙悟空' 
  from kills1 as a 
  LEFT JOIN tssrz as b 
    on a.user_id = b.id 
 WHERE b.user_name = '孙悟空' 
 GROUP BY b.user_name) e
 cross join 
 (select sum(a.kills) '猪八戒' 
  from kills1 as a 
  LEFT JOIN tssrz as b 
    on a.user_id = b.id 
 WHERE b.user_name = '猪八戒' 
 GROUP BY b.user_name) f

2、用case语句的方式实现

SELECT sum(case when user_name='孙悟空' then kills end) as '孙悟空',
  sum(case when user_name='猪八戒' then kills END) as '猪八戒',
  sum(case when user_name='沙和尚' then kills END) as '沙和尚'
   from tssrz as a
   join kills1 as b
     on a.id = b.user_id