같은 표 의 다 중 필드 를 조회 하 는 동시에 기 록 된 SQL 문 구 를 반복 합 니 다.

 


                SQL   
  ：7th string 


           （  ：peosons） 
     、    、                   select   p1.*   from   persons   p1,persons   p2   where   p1.id<>p2.id   and   p1.cardid   =   p2.cardid   and   p1.pname   =   p2.pname   and   p1.address   =   p2.address 
        ． 
         SQL   
   
1. rowid   
2. group by   
3. distinct   
   
1。 rowid   
  Oracle  rowid  ，    ，      ,    ： 
   : 
     select * from table1 a where rowid !=(select   max(rowid)   
     from table1 b where a.name1=b.name1 and a.name2=b.name2......) 
   ： 
    delete   from table1 a where rowid !=(select   max(rowid)   
     from table1 b where a.name1=b.name1 and a.name2=b.name2......) 
2.group by   
   : 
　　select count(num), max(name) from student --        ，     name   
　　group by num 
　　having count(num) >1 -- num       num   ，          
   ： 
　　delete from student 
　　group by num 
　　having count(num) >1 
　　               。 
3. distinct   -          
create table table_new as   select distinct *   from table1 minux 
truncate table table1; 
insert into table1 select * from table_new; 


               

1、           ，           （peopleId）    
select * from people 
where peopleId in (select  peopleId  from  people  group  by  peopleId  having  count(peopleId) > 1) 


2、           ，           （peopleId）   ，   rowid      
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、           （    ） 
select * from vitae a 
where (a.peopleId,a.seq) in  (select peopleId,seq from vitae group by peopleId,seq  having count(*) > 1) 


4、           （    ），   rowid      
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、           （    ），   rowid      
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) 


( ) 
    
 A        “name”， 
         “name”       ， 
                   ，“name”       ； 
Select Name,Count(*) From A Group By Name Having Count(*) > 1 
             : 
Select Name,sex,Count(*) From A Group By Name,sex Having Count(*) > 1 


( ) 
    
declare @max integer,@id integer 
declare cur_rows cursor local for select    ,count(*) from    group by     having count(*) >； 1 
open cur_rows 
fetch cur_rows into @id,@max 
while @@fetch_status=0 
begin 
select @max = @max -1 
set rowcount @max 
delete from    where     = @id 
fetch cur_rows into @id,@max 
end 
close cur_rows 
set rowcount 0 


    
＂    ＂           ，         ，            ，             ，  Name    ，                  。 


　　1、       ，      ，   
select distinct * from tableName 
　　              。 
　　             （      1 ），          
select distinct * into #Tmp from tableName 
drop table tableName 
select * into tableName from #Tmp 
drop table #Tmp 
　　                  ，           。 


　　2、                       ，       
　　         Name,Address，                
select identity(int,1,1) as autoID, * into #Tmp from tableName 
select min(autoID) as autoID into #Tmp2 from #Tmp group by Name,autoID 
select * from #Tmp where autoID in(select autoID from #tmp2) 
　　    select    Name，Address       （     autoID  ，        select       ） 


( ) 
     
select * from tablename where id in ( 
select id from tablename 
group by id 
having count(id) > 1 
)