We’ve all seen it. Some 3rd party database you’ve inherited from someone else was simply never designed with scalability and portability in mind. There’s no hope to change it, as it will break the original design and thus the original application that it is supporting.
It’s easy to grab the date from a field in a database so long as you saved a timestamp field along with your data row. However, there are often times in developing stored procedures and advanced queries where one needs to look up events in the future, or past based on some other reference point from either the data at hand, or an arbitrary date, such as in a calendar.