题目描述
leetcode题目:1633. 各赛事的用户注册率 Code
select contest_id, round(count(*)/(select count(*) from Users)*100, 2) as percentage
from Register
group by contest_id
order by percentage desc, contest_id ascCOUNT()函数
COUNT函数用法&#…
Camera
FOV: Filed of view DOV: deep of view 景深 被F f/D 衡量,f 是焦距,D 是光圈大小。
当确定好了景深后,如何光线较暗,则需要补光,或者适当延长曝光时间(快门)
分辨率、像素尺寸&…