SQL GROUP BY Statement
GROUP BY Statement:
The GROUP BY statement groups rows that have the same values into summary rows, like "find the number of customers in each country".
The GROUP BY statement is often used with aggregate functions (COUNT(), MAX(), MIN(), SUM(), AVG()) to group the result-set by one or more columns.
SELECT column_name(s) FROM table_name WHERE condition
GROUP BY column_name(s) ORDER BY column_name(s);
Example
SELECT COUNT(CustomerID), Country FROM Customers
GROUP BY Country ORDER BY COUNT(CustomerID) DESC;
This statement lists the number of customers in each country, sorted high to low