1. 题目
表: Ads
+---------------+---------+
| Column Name | Type |
+---------------+---------+
| ad_id | int |
| user_id | int |
| action | enum |
+---------------+---------+
(ad_id, user_id) 是该表的主键
该表的每一行包含一条广告的 ID(ad_id),
用户的 ID(user_id) 和用户对广告采取的行为 (action)
action 列是一个枚举类型 ('Clicked', 'Viewed', 'Ignored') 。
一家公司正在运营这些广告并想计算每条广告的效果。
广告效果用点击通过率(Click-Through Rate:CTR)来衡量,公式如下:
写一条SQL语句来查询每一条广告的 ctr ,
ctr 要保留两位小数。结果需要按 ctr 降序、按 ad_id 升序
进行排序。
查询结果示例如下:
Ads 表:
+-------+---------+---------+
| ad_id | user_id | action |
+-------+---------+---------+
| 1 | 1 | Clicked |
| 2 | 2 | Clicked |
| 3 | 3 | Viewed |
| 5 | 5 | Ignored |
| 1 | 7 | Ignored |
| 2 | 7 | Viewed |
| 3 | 5 | Clicked |
| 1 | 4 | Viewed |
| 2 | 11 | Viewed |
| 1 | 2 | Clicked |
+-------+---------+---------+
结果表:
+-------+-------+
| ad_id | ctr |
+-------+-------+
| 1 | 66.67 |
| 3 | 50.00 |
| 2 | 33.33 |
| 5 | 0.00 |
+-------+-------+
对于 ad_id = 1, ctr = (2/(2+1)) * 100 = 66.67
对于 ad_id = 2, ctr = (1/(1+2)) * 100 = 33.33
对于 ad_id = 3, ctr = (1/(1+1)) * 100 = 50.00
对于 ad_id = 5, ctr = 0.00,
注意 ad_id = 5 没有被点击 (Clicked) 或查看 (Viewed) 过
注意我们不关心 action 为 Ingnored 的广告
结果按 ctr(降序),ad_id(升序)排序
来源:力扣(LeetCode) 链接:https://leetcode-cn.com/problems/ads-performance
著作权归领扣网络所有。商业转载请联系官方授权,非商业转载请注明出处。
2. 解题
# Write your MySQL query statement below
select ad_id,
round(
ifnull(
sum(action = 'Clicked')
/(sum(action = 'Clicked')+sum(action = 'Viewed'))*100,
0)
,2) as ctr
from Ads
group by ad_id
order by ctr desc, ad_id
or
# Write your MySQL query statement below
select ad_id,
round(
ifnull(
sum(action = 'Clicked')
/(sum(action != 'Ignored'))*100,
0)
,2) as ctr
from Ads
group by ad_id
order by ctr desc, ad_id
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