What aggregate functions are used with grouping?

SELECT
    country,
    COUNT(*) AS number_of_customers, -- Number of records in each group
    SUM(order_total) AS total_revenue, -- Sum of values for each group
    AVG(order_total) AS average_order_value, -- Average value for each group
    MIN(registration_date) AS earliest_registration, -- Minimum value for each group
    MAX(last_order_date) AS latest_order -- Maximum value for each group
FROM
    customers
GROUP BY
    country; -- Grouping by the country column

Main aggregate functions used with GROUP BY:

• COUNT(): Counts the number of rows in the group.
• SUM(): Calculates the sum of values in the column for each group.
• AVG(): Calculates the average value in the column for each group.
• MIN(): Finds the minimum value in the column for each group.
• MAX(): Finds the maximum value in the column for each group.

Example table using GROUP BY and aggregate functions:

country	number_of_customers	total_revenue	average_order_value	earliest_registration	latest_order
USA	150	15000.00	100.00	2020-01-15	2023-10-26
UK	75	8000.00	106.67	2019-05-20	2023-10-25
Germany	50	6000.00	120.00	2021-03-10	2023-10-26