Restaurant Growth

Task: Compute the moving average of how much the customer paid in a seven days window.

Table: Customer

+-------------+-------------+
| Column Name | Type        |
+-------------+-------------+
| customer_id | INT         |
| name        | varchar(20) |
| visited_on  | date        |
| amount      | INT         |
+-------------+-------------+

Input: Customer table:

+-------------+---------+------------+--------+
| customer_id | name    | visited_on | amount |
+-------------+---------+------------+--------+
| 1           | Jhon    | 2019-01-01 | 100    |
| 2           | Daniel  | 2019-01-02 | 110    |
| 3           | Jade    | 2019-01-03 | 120    |
| 4           | Khaled  | 2019-01-04 | 130    |
| 5           | Winston | 2019-01-05 | 110    |
| 6           | Elvis   | 2019-01-06 | 140    |
| 7           | Anna    | 2019-01-07 | 150    |
| 8           | Maria   | 2019-01-08 | 80     |
| 9           | Jaze    | 2019-01-09 | 110    |
| 1           | Jhon    | 2019-01-10 | 130    |
| 3           | Jade    | 2019-01-10 | 150    |
+-------------+---------+------------+--------+

Output:

+------------+--------+----------------+
| visited_on | amount | average_amount |
+------------+--------+----------------+
| 2019-01-07 | 860    | 122.86         |
| 2019-01-08 | 840    | 120            |
| 2019-01-09 | 840    | 120            |
| 2019-01-10 | 1000   | 142.86         |
+------------+--------+----------------+