MySQL错误（“查询为空”）？

Question

<form method='post' action=''>
    Category name: <input type='text' name='cat_name' />
    Category description: <textarea name='cat_desc' /></textarea>
    <input type='submit' value='Add category' />
</form>

  <?php

  if($_SERVER['REQUEST_METHOD'] != 'POST')

  {
      $catname=mysql_real_escape_string('cat_name');
      $catdesc=mysql_real_escape_string('cat_desc');

      $sql = mysql_query("INSERT INTO fcategories (cat_name, cat_desc) 
      VALUES('','$catname','$catdesc')");

      $result = mysql_query($sql);
      if(!$result)
      {
          //something went wrong, display the error
          echo 'Error' . mysql_error();
      }
      else
      {
        echo 'New category successfully added.';
      }
  }

  ?>

我已经包含了与数据库的连接。当我运行代码时，表单底部出现错误。

Answer 1

$sql = "INSERT INTO fcategories (cat_name, cat_desc) 
      VALUES('$catname','$catdesc')" ;

 $result = mysql_query($sql, $dbconnection);