MYSQL 去除重复 记录
删除旧
delete from a using mix_crm_contact as a,mix_crm_contact as b where a.id<b.id and a.`telphone_num` = b.`telphone_num`
删除新
delete from a using mix_crm_contact as a,mix_crm_contact as b where a.id>b.id and a.`telphone_num` = b.`telphone_num`