Hi Liyana,
If you want to write some SQL, you can try like below:
data: lt_bkpf type standard table of BKPF,
lt_ekbe type stantdard table of EKBE.
select * from bkpf into table lt_bkpf.
select *
from ekbe
into table lt_ekbe
FOR ALL ENTRIES IN lt_bkpf
where ekbe-BELNR = lt_bkpf-AWKEY+0(10).
Offset can be used in the right of '=' in WHERE condition.