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 trade join customer on trade.t_cus = customer.c_id
where c_name = 'Tom' and year(t_time) = 2023 and t_type = 1
group by  date_format(t_time,'%Y-%m')
order by time