## Description

https://leetcode.com/problems/customer-placing-the-largest-number-of-orders/

Table: `Orders`

+-----------------+----------+ | Column Name | Type | +-----------------+----------+ | order_number | int | | customer_number | int | +-----------------+----------+ order_number is the primary key for this table. This table contains information about the order ID and the customer ID.

Write an SQL query to find the `customer_number`

for the customer who has placed **the largest number of orders**.

It is **guaranteed** that exactly one customer will have placed more orders than any other customer.

The query result format is in the following example:

Orders table: +--------------+-----------------+ | order_number | customer_number | +--------------+-----------------+ | 1 | 1 | | 2 | 2 | | 3 | 3 | | 4 | 3 | +--------------+-----------------+ Result table: +-----------------+ | customer_number | +-----------------+ | 3 | +-----------------+ The customer with number 3 has two orders, which is greater than either customer 1 or 2 because each of them only has one order. So the result is customer_number 3.

**Follow up:** What if more than one customer have the largest number of orders, can you find all the `customer_number`

in this case?

## Explanation

group by, then order by desc and limit 1.

## SQL Solution

```
# Write your MySQL query statement below
select customer_number from Orders group by customer_number order by count(order_number) desc LIMIT 1
```