MySql中数据去重的示例分析

1.查出重复数据

SELECTmember_emailFROMgroup_memberGROUPBYmember_emailHAVINGCOunT(member_email)>1

2.去除重复数据

deletefromgroup_memberwheremember_emailin(selectTEMP.member_emailfrom(SELECTmember_emailFROMgroup_memberGROUPBYmember_emailHAVINGCOUNT(member_email)>1)astemp)andidnotin(selecttemp2.idfrom(selectmin(id)asidfromgroup_memberGROUPBYmember_emailHAVINGCOUNT(member_email)>1)astemp2);