Here's another way of doing it:
with c as (
select vc,count(date) Count_VC
from zqm
where date = 'June'
group by vc
)
select c.vc,c.Count_VC,sum(case rr.date when 'June' then 1 else 0 end) Count_RR
from c
Left outer join rr on c.vc = rr.vc
where rr.owner = 'supplier'
group by c.vc,c.Count_VC