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  • SQL语句删除表中重复字段

    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)
     
    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/cyjch/p/2419428.html
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