Mysql查询不重复数据
⽤户表
app表
⽤户记录表
现在要想查出⽤户点击的记录的列表，并且按照⽤户，时间排序，去掉重复的数据
select distinct a.* from (select n.name,u.phone,n.pe from loan_record r
inner join loan_user u on u.id=r.uid
inner join loan_name n on n.id=r.appid
where r.uid in (select distinct uid from loan_record order by createdate desc) order by u.atedate desc) as a where a.name='微贷'
等价于：
select distinct a.* from (select r.uid,n.id,n.name,n.pe,n.unt,n.star from loan_name n,loan_record r where n.id=r.appid order by r.atedate desc) as a;
如果不去掉重复的，直接这样就⾏了
select u.phone,n.name,n.pe from loan_record r
inner join loan_user u on u.id=r.uid
inner join loan_name n on n.id=r.appid
order atedate desc;
同时记录下之前写的代码，读者可忽略
mysql删除重复的数据保留一条select * from (select * from (
select r.uid as uid,r.cid as cid,c.rank as rank,b.bookname as ver as ad_date as readDate,
b.id as bid,b.majorcate as majorCate,b.is_over as isOver
from record r
inner join user u on u.id=r.uid and r.uid=#{record.uid}
inner join chapter c on c.id=r.cid
inner join book b on b.id=c.bid
group by r.uid,r.cid
order by c.rank)aa ORDER BY uid asc,rank desc)cc group by bid ORDER BY readDate desc