日期:2014-05-17  浏览次数:20386 次

求一条sql语句,多表关联,join
usermessage(id,username,password,touxiang)用户信息表,表messagelist(id,title,username,time,content,class1,class2)发帖人信息表,表huifbiao(id,username,time,content,huifuid)回帖人信息表
上面三个表,如何写join语句,一条sql同时查询出回帖人个人信息和回帖人回帖的内容?

------解决方案--------------------
SQL code

-->try
select c.*,a.title,a.time,b.* from messagelist a,huifbiao b,usermessage c
where a.id=b.id and a.username=c.username

------解决方案--------------------
SQL code

select a.*,b.touxiang
from huifbiao a inner join usermessage b on a.id=b.id and a.username=b.username
left join messagelist c on a.huifuid=c.id
where c.id is not null

------解决方案--------------------
探讨

引用:
SQL code

select a.*,b.touxiang
from huifbiao a inner join usermessage b on a.id=b.id and a.username=b.username
left join messagelist c on a.huifuid=c.id
where c.id is not null

……

------解决方案--------------------
探讨

引用:
SQL code

select a.*,b.touxiang
from huifbiao a inner join usermessage b on a.id=b.id and a.username=b.username
left join messagelist c on a.huifuid=c.id
where c.id is not null

……

------解决方案--------------------
SQL code
select a.*,b.touxiang
from huifbiao a inner join usermessage b on a.id=b.id and a.username=b.username
left join (select id,title,username,min(time)time
from messagelist 
group by id,title,username) c on a.huifuid=c.id
where c.id is not null