postgresql - postgreトリガーの値を更新

Question

他のいくつかの列が変更されたときに列の値を計算しようとしているので、そのようなトリガーを作成しました。「total_points」列には常に 0 が含まれているため、何か問題があります。私は何を間違えましたか？以下の各 SELECT 呼び出しがすべてゼロ以外の値を返すことを検証しました。

CREATE FUNCTION update_order_total_points() RETURNS trigger
  LANGUAGE plpgsql
  AS $$
BEGIN
    NEW.total_points = NEW.ud * (SELECT amount FROM points WHERE abbrev = 'ud') +
                       NEW.dp * (SELECT amount FROM points WHERE abbrev = 'dp') +
                       NEW.swrv * (SELECT amount FROM points WHERE abbrev = 'swrv') +
                       NEW.sh * (SELECT amount FROM points WHERE abbrev = 'sh') +
                       NEW.jmsw * (SELECT amount FROM points WHERE abbrev = 'jmsw') +
                       NEW.sw * (SELECT amount FROM points WHERE abbrev = 'sw') +
                       NEW.prrv * (SELECT amount FROM points WHERE abbrev = 'prrv') +
                       NEW.mhsw * (SELECT amount FROM points WHERE abbrev = 'mhsw') +
                       NEW.bmsw * (SELECT amount FROM points WHERE abbrev = 'bmsw') +
                       NEW.mp * (SELECT amount FROM points WHERE abbrev = 'mp') +
                       NEW.pr * (SELECT amount FROM points WHERE abbrev = 'pr') +
                       NEW.st * (SELECT amount FROM points WHERE abbrev = 'st');
    RETURN NEW;
END;
$$;

CREATE TRIGGER fix_total_points
AFTER INSERT OR UPDATE OF ud, dp, swrv, sh, jmsw, sw, prrv, mhsw, bmsw, mp, pr, st
ON orders
FOR EACH ROW EXECUTE PROCEDURE update_order_total_points();