mysql 去掉重复数据只保留一条 在语句中加个关键字就行了；select distinct domain from 表名；查询的结果中就已经自动去重了
mysql如何删除没有主键的重复数据，只保留一条 只能用变通的办法假设表有N1，N2，N3三个字段，都是INT类型，表名是NUMBER，执行如下语句：DECLARE@TB TABLE(N1 INT，N2 INT，N3 INT)；INSERT INTO@TB SELECT TOP 1*FROM NUMBER；DELETE NUMBER；INSERT INTO NUMBER SELECT*FROM@TB；SELECT*FROM NUMBER；这样就OK了！
mysql删除重复数据只保留一条 delete from table awhere(a.catid，a.title)in(select catid，title from table group by catid，title having count(*)>；1)and 自动递增的字段 not in(select min(自动递增的字段)from table group by catid，title having count(*)>；1)and modelid=3
