如何根据此 SQL 表计算总输赢

Question

我有一个名为 games(game_id, home_id, home_score, away_id, away_score, date) 的表和一个名为 team(team_id, team_name) 的表。我需要一个 SQL 查询来根据 home_score 和 away_score 计算每支球队的总输赢和赢百分比（赢/场数）记录。

select game_id, home_score, away_score, case when home_score > away_score then 'true' else 'false ' end from game_schedule

试过这个，但不能让它做我想做的事。谢谢！

Answer 1

加入表格并使用条件聚合：

select tt.team_id, tt.team_name,
  sum(case when result > 0 then 1 else 0 end) totalwin,
  sum(case when result < 0 then 1 else 0 end) totalloss,
  100.0 * avg(case when result > 0 then 1 else 0 end) percentwin 
from (
  select t.team_id, t.team_name,
    (g.home_score - g.away_score) * case 
      when t.team_id = g.home_id then 1
      when t.team_id = g.away_id then -1
    end result 
  from team t left join games g
  on t.team_id in (g.home_id, g.away_id)
) tt
group by tt.team_id, tt.team_name

查看简化的demo。

Answer 2

反透视数据并聚合：

select team_id, sum(is_win) as num_wins, sum(is_loss) as num_losses,
       avg(is_win) as win_ratio
from ((select home_id as team_id,
              (case when home_score > away_score then 1 else 0 end) as is_win,
              (case when home_score < away_score then 1 else 0 end) as is_loss
       from games
      ) union all
      (select away_id,
              (case when away_score > home_score then 1 else 0 end) as is_win,
              (case when away_score < home_score then 1 else 0 end) as is_loss
       from games
      )
     ) g
group by team_id;