sql如何在数据库的表中查询出互为好友的两行

表的好友信息如图所示,其中friend_user_id，user_id和friend_status分别为好友的id，自己的id和与和对方的状态，其中好友的friend_id和自己的user_id为相等关系，现在小弟想知道怎么通过以上条件写出可以查询表中互为好友的两行数据，小弟是一个小白望各路大神能伸伸援手帮个小忙，蟹蟹啦！

 select a.*
 from 这个表 a
 left join 这个表 b on b.user_id = a.friend_user_id and b.friend_user_id = a.user_id

select * from a left join on a.id = b.id where a.friend_user_id = b.user_id and a.user_id = b.friend_user_id and friend_status = 'FRIEND'

select a.* from crs_friend a left join crs_friend b on a.id = b.id where a.friend_user_id = b.user_id and a.user_id = b.friend_user_id and a.friend_status = 'FRIEND' and b.friend_status = 'FRIEND'

select a.* from crs_friend a
left join crs_friend b on a.id = b.id
where a.friend_user_id = b.user_id and a.user_id = b.friend_user_id and a.friend_status = 'FRIEND' and b.friend_status = 'FRIEND'