LOV Sorting in Form

Dear All,

I have LOV column in my form, below is query used . Oracle 10g.

select distinct yy.c_activitypreauthid,member_id,yy.req_date

from   prior_authorisation_details xx,xxnmcpos_pbm_request yy

where  1=1

and    yy.c_activitypreauthid = xx.preauth_id

and    yy.pharmacy_key = (select distinct pharmacy_key from xxnmc_responsibility_pharmacy where  responsibility_id = 51338)--fnd_global.resp_id)

and    yy.req_date >= sysdate - 10

--and    member_id = '123'

--and    req_date > '01-DEC-2018'

order by req_date desc --,  member_id , req_date desc

The same is created as LOV in form, when i form is not sorting as required. In the toad it is properly sorting in form is not sorting.

Please help me

Thanks,