Performing simple arithmetic in MySQL statement or in PHP code

Question

For instance, say I have a data structure with two integer columns start and end, but I\'m actually interested in the start and difference between

Answer 1

For simple operations I would use MYSQL. I'm not a guru, but I like to keep things as simple and clean as posible so where it is possible I use MYSQL built-in functions to do the stuff that can be done with php. In other words - using MYSQL would lower the amount of code and formatting necessary to display the data.