You can probably make this even simpler, but this should work.

 select crsalp
 goto top
Scan
   lnVou_no=crsalp.you_no
   select ;
      sum(iif(type="P",cr_amount,0))as cr_amount,;
      sum(iif(type="D",dr_amount,0))as ddr_amount1;
      where vou_no=lnvou_no;
      from crsalp;
      group by vou_no;
      into cursor xyz readwrite
   wait window transform(lnvou_no) at srows()/2,scols()/2 nowait
   update cr_sum set dr_amount=xyz.cr_amount-xyz.ddr_amount1 where vou_no=lnVou_no
Endscan
 
messagebox("Done",0+16+256,"Successfully")

>Dear Sir,
>
> I have following working codes
>
>

> select crsalp
> goto top
> do while !eof()
> 	scatter memvar
> 
> 	xyz="crs"+sys(2015)
> 	select ;
> 		sum(iif(type="P",cr_amount,0))as cr_amount,;
> 		sum(iif(type="D",dr_amount,0))as ddr_amount1;
> 		where vou_no=m.vou_no;
> 		from crsalp;
> 		group by vou_no;
> 		into cursor xyz readwrite
> 
> 	wait window alltrim(str(m.vou_no)) at srows()/2,scols()/2 nowait
> 
> 	select xyz
> 	am1=cr_amount-ddr_amount1
> 
> 	select cr_sum
> 	locate for vou_no=M.vou_no
> 	if found()
> 		replace dr_amount with am1
> 	endif
> 
> 	select crsalp
> 	if !eof()
> 		skip
> 	endif
> 
> enddo
> 
> messagebox("Done",0+16+256,"Successfully")
>

>
>I need UPDADTE SQL command against above codes.
>
>Please help
>
>
>