hi Metin,
thank you for reply.
i try as under but the same time,

USE main2 
select main2                 
INDEX on DtoS(file_date) + DtoS(intervdate)+Str(num) TO ll 

USE mstr 
select mstr                 
INDEX on DtoS(file_date) + DtoS(intervdate)+Str(num) TO tt
insert INTO mstr ;
 Select * From main2 Where ;
  DtoS(file_date) + DtoS(intervdate)+Str(num) Not In ;
   (Select  DtoS(file_date) + DtoS(intervdate)+Str(num) ;
    From mstr)

thanks.
>Hi Muhammed,
>
>Did you try create indexes with "DtoS(file_date) + DtoS(intervdate)+Str(num)" both of two files?