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Sounds like you're overthinking this. If you want a date and time then you should use a data type that supports a date and time. Storing them separately as a DATE in one column and a TIME in the other makes it more complicated than it needs to be. Then the question is whether you use DATETIME or TIMESTAMP. They are mostly the same, but the key differences are that (a) DATETIMEs have a much wider range of dates they can support and (b) MySQL will reinterpret TIMESTAMPs according to server/client timezone configuration. Longer story short, DATETIME is nice for arbitrary date/time values that your application will manage (like your appointment example) while TIMESTAMP is nice for record-keeping purposes (such as when a table row was written or updated). But it doesn't really matter that much. It's perfectly okay to use DATETIME for everything, so if you're still unsure then just use that and move on to the next challenge.