如何在两个日期之间选择所有记录，而不使用日期字段?

I have a MySQL DB and I need to be able to store dates earlier then 1970 so I need a custom way to store dates. In my case, I need to be able to store dates up to the present and as far back as history goes. Obviously earlier events in history require less accuracy - days, months, even years become less important, as we do not have this historical information. The main query involving dates will be to select records between two given dates. I have a MySQL DB and I need to be able to stor