Question

我正在学习CakePHP，但是我在使用更复杂的数据库查询时遇到了很大问题。所以我想执行这种查询：

SELECT p.name, b.value
FROM books b LEFT JOIN projects p
ON b.project_id=p.id
WHERE b.created=
(SELECT max(b.created) FROM books b WHERE b.user_id=1)
AND b.user_id=1
GROUP BY p.name

有人可以帮我用cakePHP机制编写这个来准备查询吗？

Answer 1

您的代码应与此类似，假设Book e Project处于关系中（Book belongsTo Project）

$this->Book->find
(
    'all',
    array
    (
        'fields' => array('Book.value', 'Project.name'),
        'conditions' => array
        (
            'Book.created IN (SELECT MAX(Book.created) FROM books Book WHERE Book.user_id = 1)',
            'Book.user_id' => 1
        ),
        'group' => 'Project.name'
    )
);

Answer 2

使用IN子句。

   SELECT p.name, b.value
   FROM books b 
   LEFT JOIN projects p ON b.project_id=p.id
   WHERE b.created IN (SELECT max(created) FROM books  WHERE user_id=1)
   AND b.user_id=1
   GROUP BY p.name

Answer 3

如果Book和Projects是Models，您可以使用Book模型直接使用CakePHP函数进行连接，请参阅https://stackoverflow.com/a/16286735/2858188

Answer 4

请参阅此链接http://book.cakephp.org/2.0/en/models/retrieving-your-data.html#sub-queries以按照cakephp约定编写子查询。

使用join语句和子查询进行CakePHP查询准备

4 个答案: