how to write SELECT statement using tables ekko,ekpo and eket?

Hi,

I got a problem in performance tuning using below tables?

how to write SELECT statement using tables EKKO,EKPO and EKET and in conditon ( WHERE clause) use only fields

ekko~ebeln IN ebeln

ekko~loekz EQ ' '

ekko~lifnr IN lifnr

ekko~ekorg IN ekorg

ekko~ekgrp IN ekgrp

ekpo~werks IN werks

ekpo~pstyp EQ '3'

ekpo~loekz EQ space

ekpo~elikz EQ space

ekpo~menge NE 0

eket~rsnum NE space.

Thanks in Advance.

bye.