add 1322

fishercoder1534 · fishercoder1534 · commit 3f2c20c364da · 2020-02-02T10:14:40.000-08:00
diff --git a/README.md b/README.md
@@ -851,6 +851,7 @@ _If you like this project, please leave me a star._ &#9733;
 |  #  |      Title     |   Solutions   | Video         | Difficulty    | Tag          
 |-----|----------------|---------------|---------------|---------------|-------------
 |1327|[List the Products Ordered in a Period](https://leetcode.com/problems/list-the-products-ordered-in-a-period/)|[Solution](../master/database/_1327.sql) || Easy |
+|1322|[Ads Performance](https://leetcode.com/problems/ads-performance/)|[Solution](../master/database/_1322.sql) || Easy |
 |1294|[Weather Type in Each Country](https://leetcode.com/problems/weather-type-in-each-country/)|[Solution](../master/database/_1294.sql) | | Easy |
 |1280|[Students and Examinations](https://leetcode.com/problems/students-and-examinations/)|[Solution](../master/database/_1280.sql) | [:tv:](https://www.youtube.com/watch?v=ThbkV4Fs7iE)| Easy |
 |1251|[Average Selling Price](https://leetcode.com/problems/average-selling-price/)|[Solution](../master/database/_1251.sql) | | Easy |
diff --git a/database/_1322.sql b/database/_1322.sql
@@ -0,0 +1,76 @@
+--1322. Ads Performance
+--
+--Table: Ads
+--
+--+---------------+---------+
+--| Column Name   | Type    |
+--+---------------+---------+
+--| ad_id         | int     |
+--| user_id       | int     |
+--| action        | enum    |
+--+---------------+---------+
+--(ad_id, user_id) is the primary key for this table.
+--Each row of this table contains the ID of an Ad, the ID of a user and the action taken by this user regarding this Ad.
+--The action column is an ENUM type of ('Clicked', 'Viewed', 'Ignored').
+--
+--
+--A company is running Ads and wants to calculate the performance of each Ad.
+--
+--Performance of the Ad is measured using Click-Through Rate (CTR) where:
+--
+--
+--
+--Write an SQL query to find the ctr of each Ad.
+--
+--Round ctr to 2 decimal points. Order the result table by ctr in descending order and by ad_id in ascending order in case of a tie.
+--
+--The query result format is in the following example:
+--
+--Ads table:
+--+-------+---------+---------+
+--| 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 |
+--+-------+---------+---------+
+--Result table:
+--+-------+-------+
+--| ad_id | ctr   |
+--+-------+-------+
+--| 1     | 66.67 |
+--| 3     | 50.00 |
+--| 2     | 33.33 |
+--| 5     | 0.00  |
+--+-------+-------+
+--for ad_id = 1, ctr = (2/(2+1)) * 100 = 66.67
+--for ad_id = 2, ctr = (1/(1+2)) * 100 = 33.33
+--for ad_id = 3, ctr = (1/(1+1)) * 100 = 50.00
+--for ad_id = 5, ctr = 0.00, Note that ad_id = 5 has no clicks or views.
+--Note that we don't care about Ignored Ads.
+--Result table is ordered by the ctr. in case of a tie we order them by ad_id
+
+--# Write your MySQL query statement below
+select ad_id,
+ifnull(
+    round(
+        avg(
+            case
+                when action = "Clicked" then 1
+                when action = "Viewed" then 0
+                else null
+            end
+        ) * 100,
+    2),
+0)
+as ctr
+from Ads
+group by ad_id
+order by ctr desc, ad_id asc;
