按天统计

[taoeer]

select t1.curr_date, ifnull(t2.total, 0) as total_order from (
select date_format(date_add('2023-09-01',interval -t.help_topic_id day),'%Y-%m-%d') as 'curr_date' from mysql.help_topic t where t.help_topic_id<=10
) t1
left join(
select date_format(create_time, '%Y-%m-%d') as create_time, count(id) as total from t_order group by date_format(create_time,'%Y-%m-%d')
) t2 on t1.curr_date=t2.create_time order by t1.curr_date