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  • Oracle

    去除表中存在的重复数据:
    DELETE from 表 WHERE (cert_no) IN
    ( SELECT cert_no FROM 表 GROUP BY cert_no HAVING COUNT(cert_no) > 1)
     AND ROWID NOT IN (SELECT MIN(ROWID) FROM 表 GROUP BY cert_no HAVING COUNT(*) > 1);
     
    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(Id)来判断
     
    select * from 表 where Id in (select Id from 表 group byId having count(Id) > 1)
     
    2、删除表中多余的重复记录,重复记录是根据单个字段(Id)来判断,只留有rowid最小的记录
     
    DELETE from 表 WHERE (id) IN ( SELECT id FROM 表 GROUP BY id HAVING COUNT(id) > 1) AND ROWID NOT IN (SELECT MIN(ROWID) FROM 表 GROUP BY id HAVING COUNT(*) > 1);
     
    3、查找表中多余的重复记录(多个字段)
     
    select * from 表 a where (a.Id,a.seq) in(select Id,seq from 表 group by Id,seq having count(*) > 1)
     
     
    查看锁表进程SQL语句2: 
    select * from v$session t1, v$locked_object t2 where t1.sid = t2.SESSION_ID; 

    杀掉锁表进程: 
    如有記錄則表示有lock,記錄下SID和serial# ,將記錄的ID替換下面的738,1429,即可解除LOCK 
    alter system kill session '738,1429';
     
    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 表 a where (a.Id,a.seq) in (select Id,seq from 表 group by Id,seq having count(*) > 1) and rowid not in (select min(rowid) from 表 group by Id,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 表 a where (a.Id,a.seq) in (select Id,seq from 表 group by Id,seq having count(*) > 1) and rowid not in (select min(rowid) from 表 group by Id,seq having count(*)>1)
     
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  • 原文地址:https://www.cnblogs.com/fqfanqi/p/6081503.html
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