Question

我需要从两个表中获取数据，一个是类别表，第二个是子类别表。在子类别表中，我保存了类别表的主键。现在我需要从表中fecth数组。首先，我想显示类别名称及其子类别，然后显示第二个类别及其子类别。这是获取类别和子类别列表的代码。

include("admin/common/connection.php");
$userId= $_GET['user'];

if(isset($userId)) 
{
$select="select category_name,id from tbl_category where user_id='".$userId."'";
$query= mysql_query($select);
$var= array();
while($fetch_row= mysql_fetch_array($query))
{
  $cat_dish= $fetch_row['category_name'];

  $var['category'] = $cat_dish;
  $select_dish="select dish_photo,printer_location,printer_list,kitchen_display from tbl_category_dish where user_id='".$userId."' and cat_id='".$fetch_row['id']."'";
  $query_dish= mysql_query($select_dish);
  while($row= mysql_fetch_array($query_dish))
  {

    $var['dish_photo']= $row['dish_photo'];
    $var['printer_location']= $row['printer_location'];

  }

}
print_r($var);

}

Answer 1

我相信你要找的是一个JOIN声明。以下语句将替换您的两个查询，而只是使用此查询。

SELECT cd.dish_photo,cd.printer_location,cd.printer_list,cd.kitchen_display,   
    cat.category_name, cat.id   
FROM tbl_category_dish AS cd  
LEFT JOIN tbl_category AS cat ON cd.cat_id = cat.id 
WHERE cd.user_id = '".$userId."'

这些项目也可以帮助您学习和发展您的技能 1）如上所述，试试PDO to prevent SQL injection 2）检查数据库表的设置。了解database relations。

Answer 2

不评论您方法中的不安全感但回答问题，您可以在一个查询中执行此操作

$sql="select 
    a.category_name,
    a.id,
    b.dish_photo,
    b.printer_location,
    b.printer_list,
    b.kitchen_display 
    from tbl_category a, 
    tbl_category_dish 
    where user_id='" . $userid . "' 
    and b.cat_id=a.id";
while($row=mysql_fetch_array($sql)){
    if(!isset($var[$row["category_name"]])){
        $var[$row["category_name"]]=array();
    }
    $var[$row["category_name"]][]=$row;
}
print_r($var);

如何从数据库中显示类别和子类别

2 个答案: