Тема 7 Урок 7 Задача 2

SELECT *,
        SUM(total_amt) OVER (PARTITION BY EXTRACT(MONTH FROM paid_at))
FROM tools_shop.orders;

-- ИЛИ

SELECT *,
        SUM(total_amt) OVER (PARTITION BY DATE_TRUNC('month', paid_at))
FROM tools_shop.orders;