Where is the error in the request?

Question

SQL

There is a table (pictured). The task is to find the total purchases for a certain month.
I made this request, but it doesn't work. Please tell me where to correct it.

SELECT goods.purchase_date, SUM(price), MONTH(purchase_date) AS mont
FROM goods
GROUP BY mont

Answer 1

SELECT MONTH(purchase_date) AS mont, SUM(price) AS goods_sum
FROM goods
GROUP BY MONTH(purchase_date)

Addition, because life does not end tomorrow.

SELECT YEAR(purchase_date) AS goods_year,
  MONTH(purchase_date) AS goods_month, 
  SUM(price) AS goods_sum
FROM goods
GROUP BY YEAR(purchase_date), MONTH(purchase_date)
ORDER BY 1, 2