select single statement for standart table- sorting standard table specific for field

Hi everyone

Im kinda fresh for abap,

Im trying to fix old query report and this report has custom fields which always is filled by select single statements from standart tables

but I have to sort standart table  by specific field before select single statements .

here is code snippet:

SELECT SINGLE rfwrt  FROM

vbfa INTO mal_cikis_tut

WHERE vbelv EQ vbap-vbeln

AND posnv EQ vbap-posnr

AND vbtyp_n EQ 'R'

AND ( bwart =  '601' or

      bwart =  '965' or

      bwart =  '963' ).

i have to sort vbfa by vbfa-vbeln before select single statements

any help will be appreciate.

best regards