日期:2025-07-14 00:17:59 人气:1

    A+
热门评论

如何查找数据库中的重复数据

1、查找表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断 select * from peoplewhere peopleId in (select peopleId from people group by peopleId having count (peopleId) > 1) 2、删除表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断,只留有rowid最小的记录 delete from people where peopleId in (select peopleId from people group by peopleId having count (peopleId) > 1)and rowid not in (select min(rowid) from people group by peopleId having count(peopleId )>1) 3、查找表中多余的重复记录(多个字段) select * from vitae awhere (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having 扩展资料 FROM子句指定SELECT语句查询及与查询相关的表或视图。在FROM子句中最多可指定256个表或视图,它们之间用逗号分隔。 在FROM子句同时指定多个表或视图时,如果选择列表中存在同名列,这时应使用对象名限定这些列所属的表或视图。 例如在usertable和citytable表中同时存在cityid列,在查询两个表中的cityid时应使用下面语句格式加以限定: SELECTusername,citytable.cityid FROMusertable,citytable WHEREusertable.cityid=citytable.cityid 在FROM子句中可用以下两种格式为表或视图指定别名: 表名 as 别名 表名 别名 参考资料:百度百科 SELECT语句

阅读全文

如何提取出并删除数据库中重复的记录

我也想知道,于是找了下,一起看看吧 1、查找表中多余的重复记录,重复记录是根据单个字段(Id)来判断 select * from 表 where Id in (select Id from 表 group byId having count(Id) > 1) 2、删除表中多余的重复记录,重复记录是根据单个字段(Id)来判断,只留有rowid最小的记录 DELETE from 表 WHERE (id) IN ( SELECT id FROM 表 GROUP BY id HAVING COUNT(id) > 1) AND ROWID NOT IN (SELECT MIN(ROWID) FROM 表 GROUP BY id HAVING COUNT(*) > 1); 3、查找表中多余的重复记录(多个字段) select * from 表 a where (a.Id,a.seq) in(select Id,seq from 表 group by Id,seq having count(*) > 1) 4、删除表中多余的重复记录(多个字段),只留有rowid最小的记录 delete from 表 a where (a.Id,a.seq) in (select Id,seq from 表 group by Id,seq having count(*) > 1) and rowid not in (select min(rowid) from 表 group by Id,seq having count(*)>1) 5、查找表中多余的重复记录(多个字段),不包含rowid最小的记录 select * from 表 a where (a.Id,a.seq) in (select Id,seq from 表 group by Id,seq having count(*) > 1) and rowid not in (select min(rowid) from 表 group by Id,seq having count(*)>1)

阅读全文