php - 尝试从数据库检索数据时出错

Question

我正在尝试检索已存储到 php mysql 中的数据。当我尝试执行下面的代码时，出现错误:

Notice: Trying to get property of non-object in /storage/ssd5/459/2549459/public_html/x.php on line 27 0 result

x.php

<?php 
    $conn = mysqli_connect("localhost" , "id2549459_salamnti" , "0000000000" , "id2549459_tutorial");
    if($conn -> connect_error){
        die("my connection faild" . $conn -> connect_error);
    }

    $sql = "SELECT id, military_num , firstname, lastname,image from students";
    $result = $conn-> query($sql);
    if($result -> num_rows > 0){
        while($row = $result-> fetch_assoc()){
            echo "<tr> <td>" . $row["id"] . "</td> <td>" . $row["militry_num"] . "</td> <td>". $row["firstname"]. "</td><td>" . $row["lastname"] . "</td><td>" . $row["image"] . "</td> </tr>";
        }
        echo "</table>";
    }
    else{
        echo "0 result";
    }
    $conn -> close();
?>

Answer 1

有很多理由...11. mysql用户无权学生访问2.数据库中不存在列