【SQL重复记录问题的处理方法小结】教程文章相关的互联网学习教程文章

【精华摘抄】SQL查询重复记录【代码】

假设现有一张人员表(表名:Person),若想将姓名、身份证号、住址这三个字段完全相同的记录查找出来,使用 1: SELECT p1.* 2: FROM persons p1,persons p2 3: WHERE p1.id<>p2.id 4: AND p1.cardid = p2.cardid 5: AND p1.pname = p2.pname 6: AND p1.address = p2.address 可以实现该功能。删除重复记录的SQL语句 1.用rowid方法 2.用group by方法 3.用distinct方法 1。用rowid方法 据据ora...

SQL重复记录问题的处理方法小结

1、查找重复记录 ①如果只是不想在查询结果中存在重复记录, 可以加Distinct select distinct * from TestTable ②如果是想查询重复的记录及其数量 select UserID,UserName,count(*) as '记录数' from TestTable Group by UserID,UserName having count(*)>1 ③ID不重复, 但是字段重复的记录只显示一条 select * from TestTable where UserID in (select max(UserID) as UserID from TestTable group by UserName,Sex,Place) 2、删除...

删除重复记录4种方法

1.DELETE FROM tab1 a WHERE rowid < ( SELECT MAX(b.rowid) FROM tab1 b WHERE b.name = a.name AND b.price = a.price );2.DELETE FROM tab1 a WHERE EXISTS ( SELECT * FROM tab1 b WHERE b.name = a.name AND b.price = a.price AND a.rowid < b.rowid );3.DELETE FROM ta...

数据库删除重复记录

参考文章 用SQL语句,删除掉重复项只保留一条 https://www.cnblogs.com/lanliying/p/5695349.html idcard,time, company 有多条记录,idcard和company一样,但是time不一样,在一天中的不同时间。 删除这些同一天中的重复记录,只保留一条。

查询及删除重复记录的SQL语句

select * from people where 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...

PL/SQL删除重复记录

--数据库的使用过程中由于程序方面的问题有时候会碰到重复数据,重复数据导致了数据库部分设置不能正确设置……  方法一declare @max integer,@id integer declare cur_rows cursor local for select 主字段,count(*) from 表名 group by 主字段 having count(*) > 1 open cur_rows fetch cur_rows into @id,@max while @@fetch_status=0 begin select @max = @max -1 set rowcount @max delete from 表名 where 主字段 = @id fe...

删除重复记录

我们经常在数据库中有重复的记录这时候我们希望删除那些重复的记录 你不要告诉我你是一条条手动删除的哈: select distinct * into newtable form tablename drop table tablename select * into table from newtable drop table newtable 思路好了就好做.

SQL-重复记录查询的几种方法【代码】

* from people where 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 co...

SQL重复记录查询的几种方法

代码如下: 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 复制代码 代码如下: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 ...

查询表中某字段有重复记录个数的方法

--查出表中有重复的id的记录,并计算相同id的数量select id,count(id) from @table group by id having(count(id)>1) 其中,group by id,是按id字段分组查询: select id,count(id) from @table group by id 可以得到各不同id的数量合计 having(count(id)>1)判断数量大于1,也就是有重复id的记录 您可能感兴趣的文章:SQL 查询和删除重复字段数据的方法SQL重复记录查询的几种方法SQL语句实现删除重复记录并只保留一条SQL重复记...