Question

1173. Immediate Food Delivery I

中文文档

Description

Table: Delivery

+-----------------------------+---------+
| Column Name         | Type  |
+-----------------------------+---------+
| delivery_id         | int   |
| customer_id         | int   |
| order_date          | date  |
| customer_pref_delivery_date | date  |
+-----------------------------+---------+
delivery_id is the primary key (column with unique values) of this table.
The table holds information about food delivery to customers that make orders at some date and specify a preferred delivery date (on the same order date or after it).

 

If the customer's preferred delivery date is the same as the order date, then the order is called immediate; otherwise, it is called scheduled.

Write a solution to find the percentage of immediate orders in the table, rounded to 2 decimal places.

The result format is in the following example.

 

Example 1:

Input: 
Delivery table:
+-------------+-------------+------------+-----------------------------+
| delivery_id | customer_id | order_date | customer_pref_delivery_date |
+-------------+-------------+------------+-----------------------------+
| 1       | 1       | 2019-08-01 | 2019-08-02          |
| 2       | 5       | 2019-08-02 | 2019-08-02          |
| 3       | 1       | 2019-08-11 | 2019-08-11          |
| 4       | 3       | 2019-08-24 | 2019-08-26          |
| 5       | 4       | 2019-08-21 | 2019-08-22          |
| 6       | 2       | 2019-08-11 | 2019-08-13          |
+-------------+-------------+------------+-----------------------------+
Output: 
+----------------------+
| immediate_percentage |
+----------------------+
| 33.33        |
+----------------------+
Explanation: The orders with delivery id 2 and 3 are immediate while the others are scheduled.

Solutions

Solution 1: Sum

We can use the sum function to count the number of instant orders, and then divide it by the total number of orders. Since the problem requires a percentage, we need to multiply by 100. Finally, we can use the round function to keep two decimal places.

# Write your MySQL query statement below
SELECT
  ROUND(SUM(order_date = customer_pref_delivery_date) / COUNT(1) * 100, 2) AS immediate_percentage
FROM Delivery;