Question

我有一个表'活动'，列按其三个属性分组。现在我想获取从所有组中随机选择的活动ID。查询如下：

$act = $this->find('all', array('conditions' => $cond,
        'limit' => $limit,
        'fields' => array('count(*) as count, Activity.id as id'),
        'page' => $page,
        'group' => $group,
));

这些是我尝试过的，但都没有奏效。 1.创建一个应该有随机记录的自联接

    $this->bindModel(array(
        'belongsTo' => array(
            'Random' => array(
                'className' => 'Activity',
                'order' => 'rand()',
                'foreignKey' => 'id',
                'fields' => 'Random.id'
            )
        )
    ));

这失败了，因为rand（）命令被追加到最后，它只是随机化所有获取的活动。

添加了加入选项

    'joins' => array(
        array(
            'table' => 'activities',
            'alias' => 'Random',
            'type' => 'LEFT',
            'conditions' => array(
                'Activity.id = Random.id'
            ),
            'fields' => 'Random.id',
            'order' => 'rand()'
        )

这也不起作用，因为Cake

试图添加条件
'Activity.id＆gt; = floor（rand（）*（max（Activity.id） - min（Activity.id）） - min（Activity.id））'
给出了一个mysql错误

请帮帮我

Answer 1

假设您的查询有效：

$act = $this->find('all', array('conditions' => $cond,
    'limit' => $limit,
    'fields' => array('count(*) as count, Activity.id as id'),
    'page' => $page,
    'group' => $group,
    'order' => 'rand()',
    'limit' => '1' // if you only want one random activity ID
));

Answer 2

好吧终于明白了。我们需要破解蛋糕php工作的方式。代替表名，我写了一个查询来获取随机排序的记录。另请注意，联接类型是＆＃39;对＆＃39;。左连接不会产生随机排序的列表

    $activities = $this->find('all', array('conditions' => $cond,
        'page' => $page,
        'limit' => $limit,
        'fields' => array('count(*) as count, Random.id as id, max(Activity.modified) as Modified'),
        'group' => $group,
        'order' => 'Modified desc',
        'joins' => array(                
            array(
                'table' => '(select * from activities order by rand())',
                'alias' => 'Random',
                'type' => 'RIGHT',
                'conditions' => array(
                    'Activity.id = Random.id'
                ),
            )
        )
    ));

在Cakephp中逐个查询（mysql）获取随机行

2 个答案: