Customer Placing the Largest Number of Order – SQL Solution
--586 Customer Placing the Largest Number of Orders --Query the customer_number from the orders table 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 orders table is defined as follows: | Column | Type | |-------------------|-----------| | order_number (PK) | int | | customer_number | int | | order_date | date | | required_date | date | | shipped_date | date | | status | char(15) | | comment | char(200) | --Sample Input | order_number | customer_number | order_date | required_date | shipped_date | status | comment | |--------------|-----------------|------------|---------------|--------------|--------|---------| | 1 | 1 | 2017-04-09 | 2017-04-13 | 2017-04-12 | Closed | | | 2 | 2 | 2017-04-15 | 2017-04-20 | 2017-04-18 | Closed | | | 3 | 3 | 2017-04-16 | 2017-04-25 | 2017-04-20 | Closed | | | 4 | 3 | 2017-04-18 | 2017-04-28 | 2017-04-25 | Closed | | --Sample Output | customer_number | |-----------------| | 3 | --Explanation --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'. SELECT customer_number FROM orders GROUP BY customer_number ORDER BY COUNT(*) DESC LIMIT 1 ;