update columns

[blade_in_exile]

hi all

my query is either going to be so simple i should of seen the answer myself or tax everyone trying to get the answer so here goes

i have a database that holds records for football teams

one table is set up so
team_id
team
for
against
goal_diff
points

now what i would like to do is have the goal_diff column update automatically when the scores are inputted on another table which holds results

i have the for and against columns filling ok i was wondering what the best way of filling goal_diff was

would it be a code written into the sql doc itself or would it be better done when the whole thing is outputted to a php page for viewing, this way would cut down on columns although speed is not essential in this operation as there are only ever 20 teams in this table.

Regards

[masdi2t]

yo can write an after insert trigger on 'results' table which is update your 'team' table.
but, you must use at least mysql5.x