时间：2021-07-01 10:21:17 帮助过：18人阅读
1.表中有id和name 两个字段，查询出name重复的所有数据
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select * from xi a where (a.username) in (select username from xi group by username having count(*) > 1)
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2、查询出所有数据进行分组之后，和重复数据的重复次数的查询数据，先列下：
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select count(username) as ‘重复次数‘,username from xi group by username having count(*)>1 order by username desc
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3、一下为 查看别人的 结果，现列下：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
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select * from people
where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1)
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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
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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)
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3、查找表中多余的重复记录（多个字段）
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select * from vitae a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)
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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
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delete from vitae a
where (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 having count(*)>1)
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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
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select * from vitae a
where (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 having count(*)>1)
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(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；
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Select Name,Count(*) From A Group By Name Having Count(*) > 1
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如果还查性别也相同大则如下:
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Select Name,sex,Count(*) From A Group By Name,sex Having Count(*) > 1
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(三)
方法一
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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(*) >;
open cur_rows fetch cur_rows into @id,@maxwhile @@fetch_status=0
begin
select @max = @max -1
set rowcount @max
delete from 表名 where 主字段 = @id
fetch cur_rows into @id,@maxend
close cur_rows
set rowcount 0
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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
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select distinct * from tableName
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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
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select distinct * into #Tmp from tableName
drop table tableName
select * into tableName from #Tmp
drop table #Tmp
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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
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select identity(int,1,1) as autoID, * into #Tmp from tableName
select min(autoID) as autoID into #Tmp2 from #Tmp group by Name,autoID
select * from #Tmp where autoID in(select autoID from #tmp2)
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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
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select * from tablename where id in (select id from tablenamegroup by idhaving count(id) > 1)
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对一个字段查找重复记录
根据sample_code字段找到重复记录
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SELECT * FROM tb_table WHERE sample_code IN( SELECT sample_code FROM tb_table GROUP BY sample_code HAVING COUNT(sample_code) > 1 );
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对多个字段查找重复记录（这里以2个为例）
根据name和code字段找到重复记录
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SELECT * from (SELECT *, CONCAT(name,code) as nameAndCode from tb_table) t WHERE t.nameAndCode in
(
SELECT nameAndCode from (SELECT CONCAT(name,code) as nameAndCode from tb_table) tt GROUP BY nameAndCode HAVING count(nameAndCode) > 1
)
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MySQL根据某一个或者多个字段查找重复数据的sql语句
标签：aci 分组 tps count string 存在 操作方法 container cell