如何按id升序选择最后5行 - CakePHP

Question

我希望通过升序获得最后5个记录顺序.

我有一个表名chat_public_msgs,我已插入6个样本数据.我需要id asc的最后5个记录顺序.请检查下面.

表chat_public_msgs-

id  username  message  created
1    smith   hi        2014-12-14 10:14:15   
2    piter   hello     2014-12-14 10:14:20    
3    john    hi smith  2014-12-14 10:14:28
4    raj     aaa       2014-12-14 10:15:22
5   chinu    test      2014-12-14 10:15:25  
6   piter    bbbbb     2014-12-14 10:15:40  

查询 -

$fields = array('ChatPublicMsg.message','ChatPublicMsg.created','ChatPublicMsg.username');
$results = $this->ChatPublicMsg->find('all',array(
           'fields'=>$fields,
           'limit'=>5, 
           'order'=>array('ChatPublicMsg.id ASC')));

输出 -

id  username  message  created
1    smith   hi        2014-12-14 10:14:15   
2    piter   hello     2014-12-14 10:14:20    
3    john    hi smith  2014-12-14 10:14:28
4    raj     aaa       2014-12-14 10:15:22
5   chinu    test      2014-12-14 10:15:25

但是我想要这个 -

id  username  message  created  
2    piter   hello     2014-12-14 10:14:20    
3    john    hi smith  2014-12-14 10:14:28
4    raj     aaa       2014-12-14 10:15:22
5   chinu    test      2014-12-14 10:15:25  
6   piter    bbbbb     2014-12-14 10:15:40  

编辑 -

我通过升序选择最后20个订单中的查询- PHP/MySQL

select * from (
    select * from chat_public_msgs order by id desc limit 5
) tmp order by tmp.id asc

我怎么能用CakePhp格式写上面的查询？

Answer 1

您可以通过'id'DESC对结果进行排序并将记录数限制为5来执行此操作.然后使用array_reverse()来反转排序.

$fields = array('ChatPublicMsg.message','ChatPublicMsg.created','ChatPublicMsg.username');
$results = $this->ChatPublicMsg->find('all',array(
       'fields'=>$fields,
       'limit'=>5, 
       'order'=>array('ChatPublicMsg.id DESC')));
$reverse = array_reverse($results['ChatPublicMsg']);
$results['ChatPublicMsg'] = $reverse;

这假设'id'随每条记录递增.否则,您需要向表中添加时间戳字段并使用此字段进行排序.