14 - 确认率（高频 SQL 50 题基础版)

14 - 确认率

-- s为注册表，有所有用户的信息，即为主表
select s.user_id,round(sum(if(action="confirmed",1,0))/count(s.user_id),2) confirmation_rate 
from Signups s 
left join Confirmations c 
on s.user_id =c.user_id 
group by s.user_id;