• SQLSERVER 删除重复记录


    SQLSERVER 删除重复记录 


    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

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  • 原文地址:https://www.cnblogs.com/tiasys/p/2697728.html
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