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

select distinct * from tableName

select distinct * into #Tmp from tableName
drop table tableName
select * into tableName from #Tmp
drop table #Tmp

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)