Question

我必须构建以下查询，但在select max（）部分中没有想法。

有这两个表：

玩家

-------------
| id | name |
-------------
| 1  | AAAA |
-------------
| 2  | BBBB |
-------------

分数

----------------------------------------
| player_id | score | created          |
----------------------------------------
| 1         | 1080  | 2015/12/28 15:38 |
----------------------------------------
| 1         | 1199  | 2015/12/28 16:00 |
---------------------------------------|
| 2         | 2400  | 2015/12/29 10:30 |
----------------------------------------
| 2         | 2420  | 2015/12/29 10:41 |
----------------------------------------
| 2         | 2031  | 2015/12/29 11:12 |
----------------------------------------

结果我想：

----------------------------
| id | name | latest_score |
----------------------------
| 1  | AAAA | 1199         |
----------------------------
| 2  | BBBB | 2031         |
----------------------------

SQL查询＃1 - 此查询提供了我想要的上述结果

SELECT
  players.id AS id,
  players.name AS name,
  scores.player_id,
  scores.score AS latest_score,
  scores.created
FROM
  players
JOIN scores ON
  players.id = scores.player_id
WHERE
  scores.created IN(
  SELECT MAX(scores.created)
  FROM
    scores
  WHERE
    scores.player_id= player.id
)

SQL查询＃2 - @ tim-biegeleisen，也可以，或者你可以帮我构建这个查询？

SELECT p.id, p.name, s1.score AS latest_score
FROM players p INNER JOIN scores s1
ON p.id = s1.player_id
INNER JOIN
(
    SELECT s.player_id, MAX(s.created) AS latest
    FROM scores s
    GROUP BY s.player_id
) s2
ON s1.player_id = s2.player_id AND s1.created = s2.latest

目前正在尝试构建类似的内容：

    $query = $this->Players->find()
            ->select([
                "Players.id",
                "Players.name",
                "Scores.scores",
                "Scores.created"
            ])
            ->join([
                "Scores" => [
                    "table" => "scores",
                    "type" => "left",
                    "conditions" => "Players.id = Scores.player_id"
                ]
            ])
            ->where([
                "Scores.created" =>
                $this->Players->Scores->find()
                ->select(["MAX(Scores.created)"])
                ->where(["Scores.player_id = Players.id"])
            ]);

问题是，此构建器不起作用：SQLSTATE [42000]：语法错误或访问冲突：1064 SQL语法中有错误;检查与您的MariaDB服务器版本相对应的手册，以便使用接近＆＃; MAX的正确语法（`Scores__created`）FROM得分分数WHERE Scores.player_id = Players.i＆＃39;在第1行

我不想只是建立一个联接然后订购Scores.created desc，并抓住[0]来获得第一行。您知道如何构建此查询吗？请帮忙。

谢谢！

Answer 1

尝试使用CakePHP SQL函数语法：

$subquery = $this->Players->Scores->find();

$query = $this->Players->find()
    ->select([
        "Players.id",
        "Players.name",
        "Scores.scores",
        "Scores.created"
    ])
    ->join([
         "Scores" => [
             "table" => "scores",
             "type" => "left",
             "conditions" => "Players.id = Scores.player_id"
          ]
    ])
    ->where([
        "Scores.created" => $subquery
            ->select([$subquery->func()->max('Scores.created')])
            ->where(["Scores.player_id = Players.id"])
    ]);

您可以阅读有关CakePHP 3 here.

的ORM SQL函数的文档

Answer 2

我不是CakePHP专家，但我可以为您提供以下连接查询，以避免WHERE子句中的子查询。也许这可以帮助您找到解决问题的方法。

SELECT p.id, p.name, s1.score AS latest_score
FROM players p INNER JOIN scores s1
ON p.id = s1.player_id
INNER JOIN
(
    SELECT s.player_id, MAX(s.created) AS latest
    FROM scores s
    GROUP BY s.player_id
) s2
ON s1.player_id s2.player_id AND s1.created = s2.latest

CakePHP 3 - 如何在IN条件下使用子查询？

2 个答案: