题解 | 获取指定客户每月的消费额

__注意不要漏了消费类型 t_type='1'
select date_format(t_time,'%Y-%m') time,sum(t_amount) total
from trade t join customer c on t.t_cus=c.c_id
where c_name='Tom' and year(t_time)=2023 and t_type='1'
group by time
order by time