1、oracle 删除重复记录.txt 时尚，就是让年薪八千的人看上去像年薪十万。我们总是要求男人有孩子一样的眼神，父亲一样的能力。一分钟就可以遇见一个人，一小时喜欢上一个人，一天爱上一个人，但需要花尽一生的时间去忘记一个人。比如现在有一人员表 （表名：peosons）若想将姓名、身份证号、住址这三个字段完全相同的记录查询出来 select p1.* from persons p1,persons p2 where p1.id1 -按 num 分组后找出表中 num 列重复，即出现次数大于一次 删数据：delete from student group by num having count(nu
2、m) 1这样的话就把所有重复的都删除了。3.用 distinct 方法 -对于小的表比较有用create table table_new as select distinct * from table1 minux truncate table table1;insert into table1 select * from table_new;查询及删除重复记录的方法大全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
3、 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
4、录（多个字段） select * from vitae awhere (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,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 vitae awhere (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) 1)and rowid not i
5、n (select min(rowid) from vitae group by peopleId,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 vitae awhere (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) 1)and rowid not in (select min(rowid) from vitae group by peopleId,seq hav
6、ing count(*)1)(二)比方说在 A 表中存在一个字段“name” ，而且不同记录之间的“name”值有可能会相同，现在就是需要查询出在该表中的各记录之间， “name”值存在重复的项；Select Name,Count(*) From A Group By Name Having Count(*) 1如果还查性别也相同大则如下:Select Name,sex,Count(*) From A Group By Name,sex Having Count(*) 1(三)方法一declare max integer,id integerdeclare cur_rows cursor lo
7、cal for select 主字段,count(*) from 表名 group by 主字段 having count(*) ； 1open cur_rowsfetch cur_rows into id,maxwhile fetch_status=0beginselect max = max -1set rowcount maxdelete from 表名 where 主字段 = idfetch cur_rows into id,maxendclose cur_rowsset rowcount 0方法二重复记录有两个意义上的重复记录，一是完全重复的记录，也即所有字段均重复的记录，二是部分关
8、键字段重复的记录，比如 Name 字段重复，而其他字段不一定重复或都重复可以忽略。1、对于第一种重复，比较容易解决，使用select distinct * from tableName 就可以得到无重复记录的结果集。如果该表需要删除重复的记录（重复记录保留 1 条） ，可以按以下方法删除select distinct * into #Tmp from tableNamedrop table tableNameselect * into tableName from #Tmpdrop table #Tmp发生这种重复的原因是表设计不周产生的，增加唯一索引列即可解决。2、这类重复问题通常要求保留重
9、复记录中的第一条记录，操作方法如下假设有重复的字段为 Name,Address，要求得到这两个字段唯一的结果集select identity(int,1,1) as autoID, * into #Tmp from tableNameselect min(autoID) as autoID into #Tmp2 from #Tmp group by Name,autoIDselect * from #Tmp where autoID in(select autoID from #tmp2)最后一个 select 即得到了 Name，Address 不重复的结果集（但多了一个 autoID 字段，实际写时可以写在 select 子句中省去此列）(四)查询重复select * from tablename where id in (select id from tablename group by id having count(id) 1)
