sql verification code generation and complement bit

DECLARE  @a  int  =  0 , @b  VARCHAR ( 10 ) =  '' 

the CREATE  TABLE # temp2 of ( 
                        vcCode VARCHAR ( 10 ), 
                        nStatus int 
                    ) 
the while ( @a  <  10000 )
 the begin 
       - random number generator (not recommended)   
　　 - SET right = @b ( '000' + Cast (ceiling (RAND () * 10000) AS VARCHAR),. 4) 

    SET  @b  =  right ( ' 000 ' +cast(@a as varchar),4)
    if not exists(select null from #temp2 where vcCode = @b)
    begin
        insert into #temp2 values(@b,11)
        set @a = @a +1
    end
end 

insert into Table_a select * from #temp2 order by newid()