题解 | #获取指定客户每月的消费额#

SELECT DATE_FORMAT(t_time, '%Y-%m') time, SUM(t_amount) total
FROM customer c
         LEFT JOIN trade t ON c.c_id = t.t_cus
WHERE c_name = 'TOM'
  AND YEAR(t_time) = 2023
  AND t_type = 1
GROUP BY DATE_FORMAT(t_time, '%Y-%m')
ORDER BY DATE_FORMAT(t_time, '%Y-%m');