Added Question also

Author: mrinal1704

Easy/Top Travellers.sql

@@ -1,3 +1,81 @@
+-- Table: Users
+
+-- +---------------+---------+
+-- | Column Name   | Type    |
+-- +---------------+---------+
+-- | id            | int     |
+-- | name          | varchar |
+-- +---------------+---------+
+-- id is the primary key for this table.
+-- name is the name of the user.
+ 
+
+-- Table: Rides
+
+-- +---------------+---------+
+-- | Column Name   | Type    |
+-- +---------------+---------+
+-- | id            | int     |
+-- | user_id       | int     |
+-- | distance      | int     |
+-- +---------------+---------+
+-- id is the primary key for this table.
+-- user_id is the id of the user who travelled the distance "distance".
+ 
+
+-- Write an SQL query to report the distance travelled by each user.
+
+-- Return the result table ordered by travelled_distance in descending order, if two or more users travelled the same distance, order them by their name in ascending order.
+
+-- The query result format is in the following example.
+
+ 
+
+-- Users table:
+-- +------+-----------+
+-- | id   | name      |
+-- +------+-----------+
+-- | 1    | Alice     |
+-- | 2    | Bob       |
+-- | 3    | Alex      |
+-- | 4    | Donald    |
+-- | 7    | Lee       |
+-- | 13   | Jonathan  |
+-- | 19   | Elvis     |
+-- +------+-----------+
+
+-- Rides table:
+-- +------+----------+----------+
+-- | id   | user_id  | distance |
+-- +------+----------+----------+
+-- | 1    | 1        | 120      |
+-- | 2    | 2        | 317      |
+-- | 3    | 3        | 222      |
+-- | 4    | 7        | 100      |
+-- | 5    | 13       | 312      |
+-- | 6    | 19       | 50       |
+-- | 7    | 7        | 120      |
+-- | 8    | 19       | 400      |
+-- | 9    | 7        | 230      |
+-- +------+----------+----------+
+
+-- Result table:
+-- +----------+--------------------+
+-- | name     | travelled_distance |
+-- +----------+--------------------+
+-- | Elvis    | 450                |
+-- | Lee      | 450                |
+-- | Bob      | 317                |
+-- | Jonathan | 312                |
+-- | Alex     | 222                |
+-- | Alice    | 120                |
+-- | Donald   | 0                  |
+-- +----------+--------------------+
+-- Elvis and Lee travelled 450 miles, Elvis is the top traveller as his name is alphabetically smaller than Lee.
+-- Bob, Jonathan, Alex and Alice have only one ride and we just order them by the total distances of the ride.
+-- Donald didn't have any rides, the distance travelled by him is 0.
+
+-- Solution
 Select U.name as name, coalesce(sum(R.distance),0) as travelled_distance 
 from Users U left join Rides R
 on R.user_id = U.id