使用Games表为Teams表中的每个团队赢得胜利？

Question

我正在使用RoR创建一个应用来管理篮球联赛。我有两张桌子：Teams＆amp; Games。 Games表使用外键占用两个团队，并包含每个团队得分的数量，如下所示：

现在，我想列出所有球队，然后是他们的输赢记录。我不能想到一个更简单的方法，而不是一个foreach循环，它计算包含团队的游戏表中的所有记录，并且团队比其他团队更多。然后又是亏损。必须有一个更简单的方法。

有什么建议吗？

Answer 1

我同意最好不要加载所有记录并在Ruby中计算这些记录。在SQL查询中执行它会快得多。

def team_stats(team_id)
  # Wins are any game where the team played and scored higher than the other team
  wins = Game.where('(home_team_id = ? AND home_team_score > away_team_score) OR (away_team_id = ? AND home_team_score < away_team_score)', team_id, team_id).count

  # The opposite for losses
  losses = Game.where('(home_team_id = ? AND home_team_score < away_team_score) OR (away_team_id = ? AND home_team_score > away_team_score)', team_id, team_id).count

  # Ties are not accounted for

  return {:wins => wins, :losses => losses}
end