select option in function module

I have:

select-options: s_date for oijne-astdtt. in my screen.

I want to put my code in a function module, but as known that the s_date structure is



also in select statment,

select nomtk into table int_fnomtk from oijne where astdtf in s_date.

I want to pass the s_date value to the where condition in the select statment.

how i can u solve this problem.