PHP查询数据库数据时出现异常

    
        
    
    
        
Book-O-Rama Catalog Search
query($sql);
        $num_result=$result->num_rows;
        for ($i=0;$i<=$num_result;$i++){
            $row=$result->fetch_assoc();
            echo "
".($i+1)."title:";
            echo htmlspecialchars(stripslashes($row['author']));
            echo "Author:".stripslashes($row->newsauthor);
            echo "ISBN:".stripslashes($row->newsISBN);
            echo "price:".stripslashes($row->newsprice)."
";
        }
    }

    $result->free();
    $db->colse();
?>
    

$sql ="select * from books  where  ".$searchtype."  like  '%".$searchterm."%'";

        if ($result=$db->query($sql)) {
            $num_result=$result->num_rows;
            for ($i=0;$i<=$num_result;$i++){
                $row=$result->fetch_assoc();
                echo "
".($i+1)."title:";
                echo htmlspecialchars(stripslashes($row['author']));
                echo "Author:".stripslashes($row->newsauthor);
                echo "ISBN:".stripslashes($row->newsISBN);
                echo "price:".stripslashes($row->newsprice)."
";
            }
        }else{
            echo "fail.";
            exit;
        }