SQLServer刪除重復行

1.如果有ID字段，就是具有唯一性的字段 

delect table where id not in ( 
select max(id) from table group by col1,col2,col3... 
) 

group by 子句后跟的字段就是你用來判斷重復的條件，如只有col1，那么只要col1字段內容相同即表示記錄相同。 

2. 如果是判斷所有字段也可以這樣 

select * into #aa from table group by id1,id2,.... 
delete table 
insert into table 
select * from #aa 

3. 沒有ID的情況 

 

select identity(int,1,1) as id,* into #temp from tabel 
delect # where id not in ( 
select max(id) from # group by col1,col2,col3...) 
delect table 
inset into table(...) 
select ..... from #temp 

　　

4. col1+','+col2+','...col5 聯合主鍵 

 

select * from table where col1+','+col2+','...col5 in ( 
select max(col1+','+col2+','...col5) from table 
where having count(*)>1 
group by col1,col2,col3,col4 
) 

group by 子句后跟的字段就是你用來判斷重復的條件，如只有col1，那么只要col1字段內容相同即表示記錄相同。 

5. 

 

select identity(int,1,1) as id,* into #temp from tabel 
select * from #temp where id in ( 
select max(id) from #emp where having count(*)>1 group by col1,col2,col3...) 

6. 

 

select distinct * into #temp from tablename 
delete tablename 
go 
insert tablename select * from #temp Sqlclub 
go 
drop table #temp