_1173.sql

--1173. Immediate Food Delivery I
--
--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 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 preferred delivery date of the customer is the same as the order date then the order is called immediate otherwise it's called scheduled.
--
--Write an SQL query to find the percentage of immediate orders in the table, rounded to 2 decimal places.
--The query result format is in the following example:
--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                  |
--+-------------+-------------+------------+-----------------------------+
--
--Result table:
--+----------------------+
--| immediate_percentage |
--+----------------------+
--| 33.33                |
--+----------------------+
--The orders with delivery id 2 and 3 are immediate while the others are scheduled.


# Write your MySQL query statement below
select round(
    (
    100 * (select count(*) from Delivery d where d.order_date = d.customer_pref_delivery_date)/
        (select count(*) from Delivery)
        ),
    2) as immediate_percentage;