Sum total of several MySQL columns stored in another column?

Question

I have several columns in a MySQL database that I would like to add and store in another column:

column1     column2     column3    subtotal
10          10           


        

Answer 1

Well if this is just a one time deal you could do an update query like so:

UPDATE MyTable set subtotal = (column1 + column2 + column3)

If you want it to be calculated on insert, you could have a calculated column.

I would personally just wait until you need it to calculate it so that information that could easily be derived from your data isn't bloating your DB.