Select options for multiple tables

Hi,

I'm new to abap and are trying to create a report that gets information from EKKO, EKPO and EKES.

At selection screen I select want to select from multiple tables:

SELECTION-SCREEN BEGIN OF BLOCK b01 WITH FRAME TITLE text-b01.
SELECT-OPTIONS: s_eindt FOR ekes-eindt,
                 s_matnr FOR ekpo-matnr,
                 s_lifnr FOR ekko-lifnr,
                 s_werks FOR ekpo-werks OBLIGATORY .
SELECTION-SCREEN END OF BLOCK b01.

How do I manage to fill t_data with these entries when it is possible to select accross three tables?

I usually do a select * statement, fetching data from db table into an itab using WHERE e.g eindt IN s_eindt , then looping all itabs toghether to t_data.