用SQL语句删除重复记录的四种方法(1)

select [标志字段id],count(*) into temp1 from [表名]
group by [标志字段id]
having count(*)>1

insert temp1
select [标志字段id],count(*) from [表名]
group by [标志字段id]
having count(*)=1

select * into temp2 from [表名]
where 标志字段id in(select 标志字段id from temp1)

insert [表名]
select * from temp2

drop table temp1
drop table temp2

declare @max integer,@id integer
declare cur_rows cursor local for 
select id,count(*) from 表名 group by id 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 表名 where id = @id
fetch cur_rows into @id,@max
end
close cur_rows
set rowcount 0

create table a_dist(id int,name varchar(20))
insert into a_dist values(1,'abc')
insert into a_dist values(1,'abc')
insert into a_dist values(1,'abc')
insert into a_dist values(1,'abc')
exec up_distinct 'a_dist','id'
select * from a_dist
create procedure up_distinct(@t_name varchar(30)
,@f_key varchar(30))
--f_key表示是分组字段﹐即主键字段
as
begin
declare @max integer,@id varchar(30) ,
@sql varchar(7999) ,@type integer
select @sql = 'declare cur_rows cursor 
for select '+@f_key+' ,count(*) from ' 
+@t_name +' group by ' +@f_key +' having count(*) > 1'
exec(@sql)
open cur_rows 
fetch cur_rows into @id,@max 
while @@fetch_status=0 
begin 
select @max = @max -1 
set rowcount @max 
select @type = xtype from syscolumns 
where id=object_id(@t_name) and name=@f_key
if @type=56
select @sql = 'delete from '+@t_name+' 
where ' + @f_key+' = '+ @id 
if @type=167
select @sql = 'delete from '+@t_name+' 
where ' + @f_key+' = '+''''+ @id +'''' 
exec(@sql)
fetch cur_rows into @id,@max 
end 
close cur_rows 
deallocate cur_rows
set rowcount 0
end
select * from systypes
select * from syscolumns where 
id = object_id('a_dist')