收集一下这题的各种解法

字符串匹配（近似查找法）

用like来查找

select order_num, order_date 
from Orders
where order_date like '2020-01%'
order by order_date

切割字符串

select order_num, order_date 
from Orders
where left(order_date, 7) = '2020-01'
order by order_date

字符串比较

select *
from Orders
where order_date >= '2020-01-01 00:00:00' and order_date <= '2020-01-31 23:59:59'
order by order_date;

用正则来查找（效率不如like，能用like就用like）

select order_num, order_date 
from Orders
where order_date regexp '2020-01'
order by order_date

时间函数匹配

select order_num, order_date 
from Orders
where year(order_date) = '2020' and month(order_date) = '1'
order by order_date

利用date_format函数 （参考其中的匹配规则进行匹配）

select order_num, order_date 
from Orders
where date_format(order_date, '%Y-%m')='2020-01'
order by order_date