Whether it is MySQL or any other standard database management system, it is often advised that values that can be calculated shouldn’t be stored permanently in a database. This is because as the base numbers (the numbers that are used for calculations) change, so will their calculations. Additionally, performing mathematical calculations right there is much faster than repeatedly fetching database values from the server. So it is better to perform calculations as and when needed rather than storing them and retrieving them using normal MySQL functions.
This nice article on using the basic MySQL numeric functions illustrates the usage of three widely used mathematical functions namely ABS(), POW() and ROUND(). The article uses real-world examples such as calculating annualized returns on an investment.
Here is a list of all mathematical functions available in MySQL.