题解 | #获取指定客户每月的消费额#

select concat('2023-',time) as "time", total
from(
select case when mo between 1 and 9 then  lpad(mo, 2, '0')
             else mo end  as "time", total                 
from (                      
select month(t_time) as "mo", sum(t_amount) as "total"
from trade t left join customer c
on t.t_cus = c.c_id
where t_cus = 101 and t_type = 1 and t_time like '2023%'
group by month(t_time)
)t1
order by time)t2