Postgres indlejrede SQL-forespørgsel til tællefelt

Forudsat referentiel integritet og Postgres 9.4:

SELECT *, total - wins - ties AS losses
FROM (
   SELECT count(*) AS total
        , count(*) FILTER (WHERE m.winner = um.team) AS wins
        , count(*) FILTER (WHERE m.winner = 3) AS ties
   FROM   users_matches um
   JOIN   matches m ON m.id = um.match_id
   WHERE  um.user_id = 123;  -- for one given user
) sub;

Om det samlede FILTER klausul (indført med Postgres 9.4):

• Hvordan kan Jeg forenkler denne spilstatistikforespørgsel?