当我执行下面的函数时,查询执行成功,但在结果上方收到警告:
mysql_num_rows()期望参数1是资源,布尔
我该如何解决这个问题?
public function retrieve()
{
$id=JRequest::getVar('id');
$db =JFactory::getDBO();
$sql="select *
from
#__npco_car,#__npco_namayeshgah,#__npco_agahi
where
#__npco_car.car_id='$id' and
#__npco_namayeshgah.id_namayeshgah=#__npco_agahi.id_namayeshgah and
#__npco_car.car_id=#__npco_agahi.car_id
";
$db->setQuery($sql);
$db->query();
$row = $db->getNumRows();
if($row == 1) {
return $db->loadAssocList();
} else {
$db = JFactory::getDBO();
$sql="select *
from
#__npco_car,#__npco_useragahi,#__npco_user
where
#__npco_car.car_id='$id' and
#__npco_user.id_user=#__npco_useragahi.id_user and
#__npco_car.car_id=#__npco_useragahi.car_id
";
$db->setQuery($sql);
return $db->loadAssocList();
}
}
您的代码有几个问题。
- 永远不要使用未检查/未验证的请求值,甚至在示例中也不要
- 使用查询生成器
- 通过a)在构造函数中设置数据库(这在模型中已经完成)和b)在控制器中检索id来减少耦合
- 您尝试从多个表中获取所有字段(*),这些表有一些共同的列名。这是行不通的
- 看看JOIN
这将起作用:
public function retrieve($id)
{
$query = $this->_db->getQuery(true);
$query->select('#__npco_car.*')->from(array('#__npco_car', '#__npco_namayeshgah', '#__npco_agahi'));
$query->where('#__npco_car.car_id = ' . (int) $id);
$query->where('#__npco_namayeshgah.id_namayeshgah = #__npco_agahi.id_namayeshgah');
$query->where('#__npco_car.car_id = #__npco_agahi.car_id');
$this->_db->setQuery($sql);
$rows = $this->_db->loadAssocList();
if (empty($rows))
{
$query = $this->_db->getQuery(true);
$query->select('#__npco_car.*')->from(array('#__npco_car, #__npco_useragahi, #__npco_user'));
$query->where('#__npco_car.car_id = ' . (int) $id);
$query->where('#__npco_user.id_user = #__npco_useragahi.id_user');
$query->where('#__npco_car.car_id = #__npco_useragahi.car_id');
$db->setQuery($sql);
$this->_db->setQuery($sql);
$rows = $this->_db->loadAssocList();
}
return $rows;
}
这可能是您的问题。。
将您的查询更改为以下
$sql="select *
from
#__npco_car,#__npco_namayeshgah,#__npco_agahi
where
#__npco_car.car_id='".$id."' and
#__npco_namayeshgah.id_namayeshgah=#__npco_agahi.id_namayeshgah and
#__npco_car.car_id=#__npco_agahi.car_id
";
$sql="select *
from
#__npco_car,#__npco_useragahi,#__npco_user
where
#__npco_car.car_id='".$id."' and
#__npco_user.id_user=#__npco_useragahi.id_user and
#__npco_car.car_id=#__npco_useragahi.car_id
";