This Leetcode problem Immediate Food Delivery II LeetCode Solution is done in SQL.

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Immediate Food Delivery II LeetCode Solution

Problem Statement

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

The first order of a customer is the order with the earliest order date that the customer made. It is guaranteed that a customer has precisely one first order.

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

The result format is in the following example.

Example 1:
Input:

Output:

Explanation:
The customer id 1 has a first order with delivery id 1 and it is scheduled.
The customer id 2 has a first order with delivery id 2 and it is immediate.
The customer id 3 has a first order with delivery id 5 and it is scheduled.
The customer id 4 has a first order with delivery id 7 and it is immediate.
Hence, half the customers have immediate first orders.

Immediate Food Delivery II LeetCode Solution MySQL

select 
  round(
    sum(
      if(
        order_date = customer_pref_delivery_date, 
        1, 0
      )
    ) / count(*) * 100, 
    2
  ) as immediate_percentage 
from 
  Delivery 
where 
  (customer_id, order_date) in (
    select 
      customer_id, 
      min(order_date) 
    from 
      Delivery 
    group by 
      customer_id
  )Code language: SQL (Structured Query Language) (sql)