FB Phone Interview SQL/Product

Select c.date, count(distinct p.user_id)/count(distinct c.user_id)  as post_ratio
From composer c
Left join composer p on (c.date = p.date and c.user_id = p.user_id)
Where p.session_activity = ‘post’ and c.session_avtivity = ‘open’ group by 1


补充内容 (2019-8-8 13:15):
Select c.date, count(b.user_id)/sum(c.session_avtivity = ‘open’)  From composer c Left join composer p on (c.date = p.date and c.user_id = p.user_id) Where p.session_activity = ‘post’  group by 1