select  date_format(t.t_time,'%Y-%m') as time, round(sum(t.t_amount),1)  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 date_format(t.t_time,'%Y-%m')

order by time  asc

需要加强对于 date_format函数理解

%Y是四位年份

%y是两位年份