[leetcode][sql] filtering&aggregation

# Write your MySQL query statement below
# 조건
# ORDER BY COUNT(customer_number) DESC LIMIT 1

SELECT customer_number
FROM Orders
GROUP BY customer_number
ORDER BY COUNT(*) DESC
LIMIT 1;

SELECT customer_number
FROM Orders
GROUP BY customer_number
HAVING COUNT(*) = (
    SELECT MAX(order_count)
    FROM (
        SELECT COUNT(*) as order_count
        FROM Orders
        GROUP BY customer_number
    ) as counts
);

#leetcode #sql #groupby #orderbycountDescLimit