Regarding For All Entries Statement

Hi Experts,

I have simple problem,

I want to retrieve plnnr number from mapl table like this

SELECT SINGLE plnnr

matnr

FROM mapl

INTO CORRESPONDING FIELDS OF wa_mapl

WHERE matnr = wa_qals-selmatnr AND

plnty = '2'.

By using this 'plnnr' number, i want to retrieve data from another table using for all entries. like

SELECT verwmerkm

plnnr

plnkn

merknr

FROM plmk

INTO CORRESPONDING FIELDS OF TABLE it_plmk

FOR ALL ENTRIES IN it_qasr

WHERE plnkn = it_qasr-vorglfnr AND

merknr = it_qasr-merknr AND

plnnr = wa_mapl-plnnr.

My question is, Can i use this where condition (plnnr = wa_mapl-plnnr) in this statement. If i used like this, Is it retrieve data or not?

Otherwise, please give me suggession in this regard and give some coding also......

Advance thanks to all.........

Regards

Ravindra