Mysql删除重复的数据 Mysql数据去重复
MySQL数据库中查询重复数据
select*fromemployeegroupbyemp_namehavingcount(*)>1;
Mysql 查询可以删除的重复数据
selectt1.*fromemployeet1where(t1.emp_name)in(selectt4.emp_namefrom(selectt2.emp_namefromemployeet2groupbyt2.emp_namehavingcount(*)>1)t4)andt1.emp_idnotin(selectt5.emp_idfrom(selectmin(t3.emp_id)asemp_idfromemployeet3groupbyt3.emp_namehavingcount(*)>1)t5);
Mysql 删除重复的数据
deletet1fromemployeet1where(t1.emp_name)in(selectt4.emp_namefrom(selectt2.emp_namefromemployeet2groupbyt2.emp_namehavingcount(*)>1)t4)andt1.emp_idnotin(selectt5.emp_idfrom(selectmin(t3.emp_id)asemp_idfromemployeet3groupbyt3.emp_namehavingcount(*)>1)t5);
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