题解 | 获取指定客户每月的消费额

SELECT
    DATE_FORMAT(t.t_time, '%Y-%m') AS time,--只保留年月
    ROUND(SUM(t.t_amount),1) AS total
FROM
    trade t
JOIN
    customer c ON t.t_cus = c.c_id
WHERE
    t.t_type = 1--类型1表示消费
    AND c.c_name = 'TOM'
    AND YEAR(t.t_time) = 2023
GROUP BY
    time
ORDER BY
    time