SELECT DATE_FORMAT(created, '%Y') as 'year',
DATE_FORMAT(created, '%m') as 'month',
COUNT(id) as 'total'
FROM table_name
GROUP BY DATE_FORMAT(created, '%Y%m')
Ответ 2
SELECT YEAR(created) as year_val, MONTH(created) as month_val ,COUNT(*) as total
FROM testing
GROUP BY YEAR(created), MONTH(created)