DB2删除重复记录的五种情况

DB2删除重复记录得方法和其他数据库系统有何不同呢？下文为您列举了五种DB2删除重复记录的情况，希望对您有所启迪  。

　　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、DB2删除重复记录，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、DB2删除重复记录（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)

 

　　6. 处理bas_information中去重，根据t.PISField001,t.PISField011,t.areaCode
export to e:/bas_information.txt of del select s.HOUSEHOLDS, s.PISFIELD000, s.PISFIELD001, s.PISFIELD002,
    s.PISFIELD003, s.PISFIELD004, s.PISFIELD005, s.PISFIELD006, s.PISFIELD011,
    s.PISFIELD012, s.PISFIELD013, s.PISFIELD014, s.PISFIELD015, s.PISFIELD016,
    s.DEADDATE, s.QIANRUDATE, s.ZHIYE, s.JIATING, s.AREACODE, s.REG_DATE,
    s.ISLOGOUT from (select t.*,rownumber() over(partition by t.PISField001,t.PISField011,t.areaCode) as rn from bas_information t ) s where s.rn = 1;