Question

需要帮助，我尝试在Sql中使用Select if语句

 $sql = "Select *, 
 (select prod_name from #__mobile_products where prod_id=z.z_prod_id)
 as cell_name  from #__mobile_types AS z
 When z.z_status='1' and z.z_id = '".$vid."'
 else JError::raiseError(404, "Message");
        ";

目标目标是：z_status=1时显示列表，J Error时显示z_status=0。然而，它不起作用。这个功能很好用

 $sql = "Select *, 
 (select prod_name from #__mobile_products where prod_id=z.z_prod_id)
 as cell_name  from #__mobile_types AS z
 Where z.z_status='1' and z.z_id = '".$vid."'
        ";

但是，当尝试使用else语句进行修改时，它不起作用。

编辑 - 完整功能代码： -

        $database =& JFactory::getDBO();
    global $Itemid; 

 $sql = "Select *, 
 (select prod_name from #__mobile_products where prod_id=z.z_prod_id)
 as cell_name  from #__mobile_types AS z
 Where z.z_status='1' and z.z_id = '".$vid."'
        ";

    $database->setQuery($sql);
    $rows = $database->loadObjectList();
    return $rows[0];

Answer 1

您混淆了SQL和PHP以及Joomla：您编写的第二个查询是您要运行的查询。但逻辑需要在php中处理。你的sql引擎不知道“else”（这是php）或JError（这是Joomla）。不要说错误使用“ - 因为你写的只是语法错误。

$db = JFactory::getDbo();
$sql = "Select *, 
 (select prod_name from #__mobile_products where prod_id=z.z_prod_id)
 as cell_name  from #__mobile_types AS z
 Where z.z_status='1' and z.z_id = " . $db->quote($vid);
$db->setQuery($sql);
if ($result = $db->loadObject()) {
  // the query returned something, you can use the result object
  echo $result->prod_name;
} else {
  if ($db->getErrorNum()) {
    JError::raiseError(500, "Something went horribly wrong, the query returned the error ". $db->getErrorMsg());

  } else {
    echo "Your query returned no records i.e. no records satisfy the z_status=1 condition";
  }
}

最后，404“未找到”，但它指的是请求，而不是应用程序中的数据。如果查询错误输出，您可能希望返回500，而对于所有其他请求，您可能希望返回200。有关状态代码的详情，请参阅此处：http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html

Sql选择如果语句不起作用但在没有if语句的情况下作为简单函数工作

1 个答案: