问题是怎么从右边转换为左边，我自己的答案是：

select  user_name,(select eq_name from `test_game` b where b.user_name = a.user_name and b.equipment = 'arms' ) as arms,(select eq_name from `test_game` c where c.user_name = a.user_name and c.equipment = 'clothing' ) as clothing ,(select eq_name from `test_game` d where d.user_name = a.user_name and d.equipment = 'shoe' ) as shoe from `test_game` a  group by a.user_name;

感觉子查询太多了，效率有点低，哪位大神帮忙优化一下？