Question

我正在尝试返回matches范围内的所有round，每个回合可以有不同的匹配项。所以我写了这个查询：

SELECT m.id, m.round_id, m.gameweek
 FROM `match` m
 LEFT JOIN competition_rounds r ON m.round_id = r.id
 LEFT JOIN competition_seasons s ON r.season_id = s.id
 LEFT JOIN competition c ON c.id = s.competition_id
 WHERE 1 AND
 m.status = 5 AND
 m.round_id IN (488, 489, 490, 491) AND
 m.gameweek = (SELECT MAX(m2.gameweek)
                FROM `match` m2
                WHERE m2.round_id IN (488, 489, 490, 491))

现在的问题是结果只返回ID为488的回合的matches，为什么忽略其他回合？谢谢。

Answer 1

我认为您可能想要：

SELECT m.id, m.round_id, m.gameweek
 FROM `match` m
 LEFT JOIN competition_rounds r ON m.round_id = r.id
 LEFT JOIN competition_seasons s ON r.season_id = s.id
 LEFT JOIN competition c ON c.id = s.competition_id
 WHERE 1 AND
 m.status = 5 AND
 m.round_id IN (488, 489, 490, 491) AND
 m.gameweek = (SELECT MAX(m2.gameweek)
                FROM `match` m2
                WHERE m2.round_id = m.round_id))

Answer 2

我猜这个查询就足够了：

SELECT m.id, m.round_id, m.gameweek
FROM `match` m
WHERE 1 AND
      m.status = 5 AND
      m.round_id IN (488, 489, 490, 491) AND
      m.gameweek = (SELECT MAX(m2.gameweek)
                    FROM `match` m2
                    WHERE m2.round_id = m.round_id AND
                          m2.status = m.status
                   );

也就是说，您可能还需要考虑状态。而且，除非您真的想要结果重复，否则不需要JOIN。

Answer 3

您需要一个相关的子查询：

SELECT m.id, m.round_id, m.gameweek
 FROM `match` m
 LEFT JOIN competition_rounds r ON m.round_id = r.id
 LEFT JOIN competition_seasons s ON r.season_id = s.id
 LEFT JOIN competition c ON c.id = s.competition_id
 WHERE 1 AND
 m.status = 5 AND
 m.round_id IN (488, 489, 490, 491) AND
 m.gameweek = (SELECT MAX(m2.gameweek)
                FROM `match` m2
                WHERE m2.round_id = m.round_id)

IN运算符不会返回该范围内的所有记录

3 个答案: