Trips and Users

Author: ignacio-chiazzo

LeetcodeProblems/Databases/Trips_and_Users.sql

@@ -0,0 +1,71 @@
+/*
+Trips and Users
+https://leetcode.com/problems/trips-and-users/
+
+SQL Schema
+The Trips table holds all taxi trips. Each trip has a unique Id, while Client_Id and Driver_Id are both foreign keys to the Users_Id at the Users table. Status is an ENUM type of (‘completed’, ‘cancelled_by_driver’, ‘cancelled_by_client’).
+
++----+-----------+-----------+---------+--------------------+----------+
+| Id | Client_Id | Driver_Id | City_Id |        Status      |Request_at|
++----+-----------+-----------+---------+--------------------+----------+
+| 1  |     1     |    10     |    1    |     completed      |2013-10-01|
+| 2  |     2     |    11     |    1    | cancelled_by_driver|2013-10-01|
+| 3  |     3     |    12     |    6    |     completed      |2013-10-01|
+| 4  |     4     |    13     |    6    | cancelled_by_client|2013-10-01|
+| 5  |     1     |    10     |    1    |     completed      |2013-10-02|
+| 6  |     2     |    11     |    6    |     completed      |2013-10-02|
+| 7  |     3     |    12     |    6    |     completed      |2013-10-02|
+| 8  |     2     |    12     |    12   |     completed      |2013-10-03|
+| 9  |     3     |    10     |    12   |     completed      |2013-10-03| 
+| 10 |     4     |    13     |    12   | cancelled_by_driver|2013-10-03|
++----+-----------+-----------+---------+--------------------+----------+
+The Users table holds all users. Each user has an unique Users_Id, and Role is an ENUM type of (‘client’, ‘driver’, ‘partner’).
+
++----------+--------+--------+
+| Users_Id | Banned |  Role  |
++----------+--------+--------+
+|    1     |   No   | client |
+|    2     |   Yes  | client |
+|    3     |   No   | client |
+|    4     |   No   | client |
+|    10    |   No   | driver |
+|    11    |   No   | driver |
+|    12    |   No   | driver |
+|    13    |   No   | driver |
++----------+--------+--------+
+Write a SQL query to find the cancellation rate of requests made by unbanned users (both client and driver must be unbanned) between Oct 1, 2013 and Oct 3, 2013. The cancellation rate is computed by dividing the number of canceled (by client or driver) requests made by unbanned users by the total number of requests made by unbanned users.
+
+For the above tables, your SQL query should return the following rows with the cancellation rate being rounded to two decimal places.
+
++------------+-------------------+
+|     Day    | Cancellation Rate |
++------------+-------------------+
+| 2013-10-01 |       0.33        |
+| 2013-10-02 |       0.00        |
+| 2013-10-03 |       0.50        |
++------------+-------------------+
+*/
+
+-- solution 1
+SELECT trips_per_date.Request_at AS "Day", Round(coalesce(cancelled_trips.count_of_cancelled_trips, 0) / trips_per_date.count_of_trips, 2) as "Cancellation Rate"
+FROM (
+        SELECT Trips.Request_at, count(*) as count_of_cancelled_trips
+        FROM  Trips JOIN Users as users_drivers ON Trips.Driver_Id = users_drivers.Users_Id JOIN Users as users_clients ON Trips.Client_Id = users_clients.Users_Id
+        WHERE users_drivers.Banned = "No" AND users_clients.Banned = "No" AND (Trips.Status = "cancelled_by_driver" OR Trips.Status = "cancelled_by_client") 
+        GROUP BY Trips.Request_at
+    ) as cancelled_trips RIGHT JOIN ( 
+        SELECT Request_at, count(*) as count_of_trips 
+        FROM Trips JOIN Users as users_drivers ON Trips.Driver_Id = users_drivers.Users_Id JOIN Users as users_clients ON Trips.Client_Id = users_clients.Users_Id
+        WHERE users_drivers.Banned = "No" AND users_clients.Banned = "No"
+        Group by Request_at
+    ) as trips_per_date ON cancelled_trips.Request_at = trips_per_date.Request_at
+WHERE trips_per_date.Request_at >= Date("2013-10-01") AND trips_per_date.Request_at <= Date("2013-10-03")
+ORDER BY trips_per_date.Request_at
+
+-- solution 2
+SELECT Trips.Request_at AS "Day", ROUND(count(IF(Trips.Status = "cancelled_by_driver" OR Trips.Status = "cancelled_by_client",TRUE,null)) / count(*), 2) as "Cancellation Rate"
+FROM  Trips JOIN Users as users_drivers ON Trips.Driver_Id = users_drivers.Users_Id JOIN Users as users_clients ON Trips.Client_Id = users_clients.Users_Id
+WHERE users_drivers.Banned = "No" AND users_clients.Banned = "No" -- AND ()  
+    AND Trips.Request_at >= Date("2013-10-01") AND Trips.Request_at <= Date("2013-10-03")
+GROUP BY Trips.Request_at
+ORDER BY Trips.Request_at

README.md

@@ -81,8 +81,7 @@ To run a specific problem in your console, go to the file test, add the call to
 ### Databases
 | Problems | Level | Link |
 |-|-|-|
-Human Traffic of Stadium
-
+| [Trips and Users](/LeetcodeProblems/Databases/Trips_and_Users.sql) | Hard | https://leetcode.com/problems/trips-and-users/ |
 | [Human Traffic of Stadium](/LeetcodeProblems/Databases/Human_Traffic_of_Stadium.sql) | Hard | https://leetcode.com/problems/human-traffic-of-stadium |
 | [Rank Scores](/LeetcodeProblems/Databases/Rank_Scores.sql) | Medium | https://leetcode.com/problems/rank-scores |
 | [Consecutive Numbers](/LeetcodeProblems/Databases/Consecutive_Numbers.sql) | Medium | https://leetcode.com/problems/consecutive-numbers |