mysql 查询所有评论以及回复

问题描述

表设计如下

question(id, user_id,content)answer (id,question_id,user_id,content)reply (id,answer_id, user_id,content)

请问要怎么一次性查询所有的评论和回复啊目前用group by和group_concat实现不了额..

问题解答

我理解：question是问题表，罗列所有的提问answer 是回复表，对某个具体问题的回复，用question_id与question表中的id做关联reply 是对某个回复的评论，用answer_id与answer表中的id做关联以下代码，基于以上理解

select t1.q_id as 问题id, t1.q_user_id as 提问者id, t1.q_content as 问题内容, t2.a_id as 回复id, t2.a_user_id as 回复者id, t2.a_content as 回复内容, t3.r_id as 评论id, t3.r_user_id as 评论者id, t3.r_content as 评论内容from (select id as q_id ,user_id as q_user_id ,content as q_contentfrom question) t1 -- 所有的问题列表，用id做唯一性的区分left outer join(select id as a_id ,question_id ,user_id as a_user_id ,content as a_contentfrom answer) t2on t1.q_id = t2.question_id -- 每个question_id对应的回复left outer join(select id as r_id ,answer_id ,user_id as r_user_id ,content as r_content) t3 on t2.a_id = t3.answer_id -- 每个answer_id对应的评论回答2：

select reply.,answer.,question.* fromreply right join answer onreply.answer_id = answer.I’dright join question onanswer.question_id = question.idWhere question.id =(查找的question.id)