eat not in nbsp per 根據 pan Nid res 多余

建表語句
CREATE TABLE Persons
(
PersonID int,
LastName varchar(255),
FirstName varchar(255),
Address varchar(255),
City varchar(255)
);

insert into Persons values(1,‘a‘,‘aa‘,‘aaa‘,‘aaaa‘);
insert into Persons values(1,‘a‘,‘aa‘,‘aaa‘,‘aaaa‘);
insert into Persons values(1,‘a‘,‘aa‘,‘aaa‘,‘aaaa‘);
insert into Persons values(1,‘a‘,‘aa‘,‘aaa‘,‘aaaa‘);
insert into Persons values(2,‘a‘,‘aa‘,‘aaa‘,‘aaaa‘);
insert into Persons values(2,‘a‘,‘aa‘,‘aaa‘,‘aaaa‘);
insert into Persons values(3,‘a‘,‘aa‘,‘aaa‘,‘aaaa‘);
insert into Persons values(3,‘a‘,‘aa‘,‘aaa‘,‘aaaa‘);
insert into Persons values(4,‘a‘,‘aa‘,‘aaa‘,‘aaaa‘);
insert into Persons values(5,‘a‘,‘aa‘,‘aaa‘,‘aaaa‘);

select * from Persons order by PersonID;
PERSONID LASTNAME FIRSTNAME ADDRESS 　　 CITY
1 1 　　　　　　 a 　　　　aa 　　　　　　aaa 　　 aaaa
2 1 　　　　　　 a 　　　　 aa 　　　　　　aaa 　　 aaaa
3 1 　　　　　　 a 　　　　aa 　　　　　　 aaa 　　aaaa
4 1 　　　　　　 a 　　　　aa 　　　　　　aaa 　　aaaa
5 2 　　　　　　 a 　　　　 aa 　　　　　　aaa 　　aaaa
6 2 　　　　　　 a 　　　　 aa 　　　　　　aaa 　　aaaa
7 3 　　　　　　a 　　　　aa 　　　　　　aaa 　　aaaa
8 3 　　　　　　a 　　　　aa 　　　　　　aaa 　　 aaaa
9 4 　　　　　　 a 　　　　aa 　　　　　　aaa 　　aaaa
10 5 　 　　　　 a 　　　　aa 　　　　　　aaa 　　aaaa


1、查找表中多余的重復記錄，重復記錄是根據單個字段（PersonID）來判斷。

select * from Persons where PersonID in ( select PersonID from Persons group by PersonID having(count(PersonID))>1);
order by PersonID;

PERSONID LASTNAME FIRSTNAME ADDRESS CITY
1 a aa aaa aaaa
1 a aa aaa aaaa
1 a aa aaa aaaa
1 a aa aaa aaaa
2 a aa aaa aaaa
2 a aa aaa aaaa
3 a aa aaa aaaa
3 a aa aaa aaaa


2、刪除表中多余的重復記錄，重復記錄是根據單個字段（PersonID）來判斷，只留有rowid最小的記錄。
select * from Persons
where PersonID in (select PersonID from Persons group by PersonID having count(PersonID) > 1)
and rowid not in (select min(rowid) from Persons group by PersonID having count(PersonID )>1)
order by PersonID;

delete from Persons
where PersonID in (select PersonID from Persons group by PersonID having count(PersonID) > 1)
and rowid not in (select min(rowid) from Persons group by PersonID having count(PersonID )>1)

PERSONID LASTNAME FIRSTNAME ADDRESS CITY
1 a aa aaa aaaa
1 a aa aaa aaaa
1 a aa aaa aaaa
2 a aa aaa aaaa
3 a aa aaa aaaa


3、查找表中多余的重復記錄（多個字段）
select * from Persons a
where (a.PersonID,a.City) in (select PersonID,City from Persons group by PersonID,City having count(*) > 1)
order by PersonID;

PERSONID LASTNAME FIRSTNAME ADDRESS CITY
1 a aa aaa aaaa
1 a aa aaa aaaa
1 a aa aaa aaaa
1 a aa aaa aaaa
2 a aa aaa aaaa
2 a aa aaa aaaa
3 a aa aaa aaaa
3 a aa aaa aaaa


4、刪除表中多余的重復記錄（多個字段），只留有rowid最小的記錄
select * from Persons a
where (a.PersonID,a.City) in (select PersonID,City from Persons group by PersonID,City having count(*) > 1)
and rowid not in (select min(rowid) from Persons group by PersonID,City having count(*)>1)
order by PersonID;

delete from Persons a
where (a.PersonID,a.City) in (select PersonID,City from Persons group by PersonID,City having count(*) > 1)
and rowid not in (select min(rowid) from Persons group by PersonID,City having count(*)>1)

PERSONID LASTNAME FIRSTNAME ADDRESS CITY
1 a aa aaa aaaa
1 a aa aaa aaaa
1 a aa aaa aaaa
2 a aa aaa aaaa
3 a aa aaa aaaa


5、查找表中多余的重復記錄（多個字段），不包含rowid最小的記錄
select * from Persons a
where (a.PersonID,a.City) in (select PersonID,City from Persons group by PersonID,City having count(*) > 1)
and rowid not in (select min(rowid) from Persons group by PersonID,City having count(*)>1)
and rowid not in (select min(rowid) from Persons group by PersonID,seq having count(*)>1)
order by PersonID;

PERSONID LASTNAME FIRSTNAME ADDRESS CITY
1 a aa aaa aaaa
1 a aa aaa aaaa
1 a aa aaa aaaa
2 a aa aaa aaaa
3 a aa aaa aaaa

oracel 查詢刪除重復記錄的幾種方法