qq_30558677
黑色幽默y
2018-03-19 03:56
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sql 查询重复数据个数并按照次数分组

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10条回答 默认 最新

  • cxfidc01
    红帽01 2018-03-19 04:26
    已采纳
    SELECT  *
    FROM    ( SELECT    counts ,
                        COUNT(*) counts2
              FROM      ( SELECT    name ,
                                    COUNT(*) AS counts
                          FROM      talbe***
                          GROUP BY  name
                        ) a
              GROUP BY  counts
            ) a
    ORDER BY counts
    
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  • zhao_qun
    zhao_qun 2018-03-19 04:01

    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
    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 tableName
    drop table tableName
    select * into tableName from #Tmp
    drop 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 tableName
    select min(autoID) as autoID into #Tmp2 from #Tmp group by Name,autoID
    select * 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)

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  • SNOYC
    SNOYC 2018-03-19 04:02

    SELECT Name,COUNT(Name) AS ACOUNT FROM 表明 GROUP BY Name ORDER BY ACOUNT ASC

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  • hengfengbo
    hengfengbo 2018-03-19 05:09

    SELECT *
    FROM ( SELECT counts ,
    COUNT(*) counts2
    FROM ( SELECT name ,
    COUNT(*) AS counts
    FROM talbe***
    GROUP BY name
    )
    GROUP BY counts
    )
    ORDER BY counts

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  • lvleshuai
    lvleshuai 2018-03-19 05:10

    涨知识了,谢谢大家慷慨分享了哈s

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  • u011542482
    小豆存在了 2018-03-19 05:10

    group by

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  • lvleshuai
    lvleshuai 2018-03-19 05:10

    grop by 就可以了啊

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  • qq_36735325
    qq_36735325 2018-03-19 05:45

    delete YourTable

    where [id] not in (
    select max([id]) from YourTable

    group by (name + value))

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  • zhuziheng126
    Sinberian 2018-03-19 05:56

    select * from tablename where id in (
    select id from tablename
    group by id
    having count(id) > 1
    )

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  • qq_34692757
    qq_34692757 2018-03-19 03:57

    查询有重复数据的记录
    select * from F group by a,b,c,d having count(*)>1
    删除重复一模一样的记录,只保留一条记录
    select distinct * into #Tmp from tableName
    drop table tableName
    select * into tableName from #Tmp
    drop table #Tmp
    SQL删除重复数据方法
    例如:
    id name value
    1 a pp
    2 a pp
    3 b iii
    4 b pp
    5 b pp
    6 c pp
    7 c pp
    8 c iii
    id是主键
    要求得到这样的结果
    id name value
    1 a pp
    3 b iii
    4 b pp
    6 c pp
    8 c iii

    方法1
    delete YourTable

    where [id] not in (
    select max([id]) from YourTable

    group by (name + value))

    方法2
    delete a
    from 表 a left join(
    select id=min(id) from 表 group by name,value
    )b on a.id=b.id
    where b.id is null

    查询及删除重复记录的SQL语句
    查询及删除重复记录的SQL语句
    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 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(peopleId )>1)
    3、查找表中多余的重复记录(多个字段)
    select * from vitae a
    where (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 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)

    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 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)
    (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 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
    fetch cur_rows into @id,@max
    end
    close cur_rows
    set 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 tableName
    drop table tableName
    select * into tableName from #Tmp
    drop 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 tableName
    select min(autoID) as autoID into #Tmp2 from #Tmp group by Name,autoID
    select * 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
    )

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