can you check this below queries if it is solve your problem or not.
select s.part_no,s.part_name,i.qty as inwardQty,p.qty as issueQty
from stock s
left join
(select part_no,sum(qty) as qty,date from inward group by part_no) i on s.part_no = i.part_no
left join
(select part_no,sum(qty) as qty,date from issue group by part_no) p on s.part_no = p.part_no
WHERE month(i.date)=6,month(p.date)=6
select s.part_no,s.part_name,i.qty as inwardQty,p.qty as issueQty
from stock s
left join
(select part_no,sum(qty) as qty from inward WHERE month(i.date)=6 group by part_no) i on s.part_no = i.part_no
left join
(select part_no,sum(qty) as qty from issue WHERE month(p.date)=6 group by part_no) p on s.part_no = p.part_no