select substr(t.t_time,1,7) as time, 
sum(t.t_amount) as total
from trade t
join customer c on t.t_cus = c.c_id
where c.c_name = 'Tom'
and year(t.t_time) =2023
and t.t_type =1
group by substr(t.t_time,1,7)
order by time

简单查询