SQL cell formula possible? Possibly a dumb question...

hello all!

I have two cols in a MySQL database date1 and date2.

I need a third col that needs to be: time = date2 - date1

Rather than having to perform this operation with a select calculate and insert statement I was wondering if there was a way to put a formula of some sort in the time col that would automatically calculate the difference in the dates?

I guess the closest real-world example I can provide is something similar to what you could do in Excel with formulas and equations.

*Disclaimer: this is my first venture into MySQL math :)

Thanks in advance for any guidance!