MySQL count(col) 那 returns null

Question

我有 3 个表：

团队（id_team，姓名，id_season）
Teams_Stats（id_stats、id_game、id_team、胜利、失败）
季节（id_season，名称，nbr_teams）

我正在尝试提取特定赛季（在本例中为 2015 年）每支球队的胜利次数。

这就是我目前所拥有的，但它 returns 对所有团队都是 0。

我的 SQL 语法：

SELECT T.name, count(a.victory) as Wins
FROM Teams T, Seasons S
  LEFT JOIN 
    (SELECT TS.id_team, TS.victory FROM Teams_Stats TS WHERE TS.victory = 1) a
  ON a.id_team = 'T.id_team'
WHERE T.id_season = S.id_season AND S.name = '2015'
GROUP BY T.nom 
ORDER BY T.nom

我做错了什么？

谢谢:)

Answer 1

尝试将您的查询修改得有点像

SELECT T.name, count(TS.victory) as Wins
FROM Teams T
JOIN Seasons S ON T.id_season = S.id_season AND S.name = '2015'
LEFT JOIN Teams_Stats TS ON TS.id_team = T.id_team AND TS.victory = 1
GROUP BY T.name 
ORDER BY T.name

MySQL count(col) 那 returns null

MySQL count(col) that returns null

mysql

count