sql语句返回每月金额总和

SELECT COALESCE(SUM(cgprice), 0) AS total_amount FROM ( SELECT 1 AS month_num UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9 UNION SELECT 10 UNION SELECT 11 UNION SELECT 12 ) AS months LEFT JOIN buy ON MONTH(sqdate) = month_num AND YEAR(sqdate) = 2023 GROUP BY month_num;