独角兽企业重金招聘Python工程师标准>>>
删除表中重复记录，只保留一条：
delete from 表名 where 字段ID in (select * from (select max(字段ID) from 表名 group by 重复的字段 having count(重复的字段) > 1) as b);
实例： 2.当想要为某一个表建立一个唯一索引，由于表中有重复记录而无法进行时，需要删除重复记录。 例表 dept id_no id_name 100 'AAA' 101 'BBB' 102 'CCC' 103 'DDD' 100 'EEE' 100 'FFF' 103 'GGG' 请写一条(或一组)SQL语句，删除重复的行，但重复的行中需要保留一行， 如上表，id_no=100需要删除2行，保留一行，id_no=101需要删除一行保留一行id_no=102和103则不删
delete from dept where id_no not in ( select * from (select max(id_no) from dept group by id_no having count(id_no)>1) b);
以上转自/blog/497359
但是我的需求不太一样， | id | createTime | labId | pubId | +-----+---------------------+-------+--------------------------------------+ | 171 | -05-22 21:49:11 | 1 | d4165953-2245-4b8c-b21d-8c08d519f66e | | 172 | -05-22 21:49:11 | 2 | d4165953-2245-4b8c-b21d-8c08d519f66e | | 173 | -05-22 21:49:11 | 6 | d4165953-2245-4b8c-b21d-8c08d519f66e | | 174 | -05-22 21:49:11 | 5 | d4165953-2245-4b8c-b21d-8c08d519f66e | | 175 | -05-22 21:49:11 | 2 | d4165953-2245-4b8c-b21d-8c08d519f66e | | 176 | -05-22 21:49:11 | 6 | d4165953-2245-4b8c-b21d-8c08d519f66e | | 177 | -05-22 21:49:11 | 5 | d4165953-2245-4b8c-b21d-8c08d519f66e | | 178 | -07-03 15:20:07 | 2 | d5308254-3b52-4ada-8e10-16b6a764c5e5 | | 179 | -07-03 15:36:00 | 2 | d4bc80b4-b57b-4049-9ab3-8f45102fae91 | | 180 | -07-04 21:05:26 | 4 | f8ccee8f-d93c-41cc-8d2f-28ada7ea4b07 | 我需要把labId和pubId相同的重复记录删掉，只要labId和pubId有一项不同就不算重复记录。 delete from t_publishandlabel where id not in ( select * from(select max(id) from t_publishandlabel group by pubId,labId)b);
