mysql如何实现行转列

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