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  • SQL-重复记录查询的几种方法

    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
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  • 原文地址:https://www.cnblogs.com/dekevin/p/5592956.html
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