Предполагая, что ваши таблицы имеют следующую структуру:
TABLE team
id integer autoincrement primary key,
name varchar,
pointsfavor integer,
pointscontra integer
TABLE game
id integer autoincrement primary key,
team1_id integer,
team2_id integer,
score1 integer, /*score for team1*/
score2 integer /*score for team2*/
Ваш оператор обновления может выглядеть примерно так:
UPDATE team
INNER JOIN game g1 ON (team.id = g1.team1_id)
INNER JOIN game g2 ON (team.id = g2.team2_id)
SET pointsfavor = pointsfavor
+ IF(g1.score1 > g1.score2, g1.score1 - g1.score2, 0)
+ IF(g2.score2 > g2.score1, g2.score2 - g2.score1, 0)
, pointscontra = pointscontra
+ IF(g1.score1 < g1.score2, g1.score2 - g1.score1, 0)
+ IF(g2.score2 < g2.score1, g2.score1 - g2.score2, 0)
WHERE game.id = 10;