how can I make a table field predefined in mysql? : I've not worked on such case before so asking you . like I'll create a table where inside the table fields field3=field1+field2 by default. mean i don't need to make it on frontend.
check the imaga-
[enter image description here][1]

please give a suggestion.

Thanks 


  [1]: https://i.stack.imgur.com/tO5ks.jpg