select variant_name, count(id_for_vendor) as total_sent, count(SubID) as total_sent,
(cast(count(SubID) as float))/(cast(count(id_for_vendor) as float)) as RetentionRatio
From
(select a.*,Sub.id_for_vendor as SubID,Sub.device_timestamp
from public.Facetune2_usage_ab_test_info_all as A left join
public.Facetune2_usage_store_user_subscribed as Sub
on (a.id_for_vendor=Sub.id_for_vendor and a.device_timestamp < Sub.device_timestamp)) as Y
group by variant_name