我必须构建以下查询,但在select max()部分中不知道。
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 |
----------------------------------------
结果我希望拥有:
----------------------------
| id | name | latest_score |
----------------------------
| 1 | AAAA | 1199 |
----------------------------
| 2 | BBBB | 2031 |
----------------------------
SQL查询#1-此查询给出我想要的上述结果
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-通过@ tim-biegeleisen,也可以使用,所以还是可以帮助我建立此查询?
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
目前正在尝试建立类似:
$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,此生成器不起作用:SQLSTATE [42000]:语法错误或访问冲突:1064您的SQL语法有错误;您可能无法使用它。检查与您的MariaDB服务器版本相对应的手册以获取正确的语法,以在第1行的'MAX(`Scores__created`)FROM scores Scores WHERE Scores.player_id = Players.i'附近使用
我不想只是建立一个联接,然后订购Scores.created
desc,并抓住[0]
以获得第一行。您知道如何建立此查询吗?请帮忙。
谢谢!
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"])
]);
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我来说两句