今天是两个（DATETIME）列之间的今天？ （空或全零计为未绑定的上限/下限）

Question

我有一个产品表和两个DATETIME列，一个用于start_date，另一个用于end_date。

如何检查特定产品ID是否在开始日期和结束日期之间？但是，如果其中一个或两个为NULL（默认值），则接受此下限/上限为无限制，如果产品仍在另一个范围内（如果已设置），则返回该产品。如果两个边界都设置为NULL，则始终返回产品。

Answer 1

select *
from your_table
where
product_id = 1 AND
(
   (CURDATE() between start_date and end_date) 
   or (CURDATE() >= start_date and end_date is null) 
   or (CURDATE() <= end_date and start_date is null)
   or (start_date is null and end_date is null)
)

Answer 2

select case when ('2012-06-26' between start_date and end_date) 
                or ('2012-06-26' >= start_date and end_date is null) 
                or ('2012-06-26' <= end_date and start_date is null)
            then 1
            else 0
            end as is_between_dates
from your_table
where product_id = 1