Question

我正在使用以下代码来检索存储在数据库中的学生信息。问题是，如果我使用if下面的代码然后一切正常，除了我只得到一个与该学生相关的教师详细信息，如果我使用while那么它会一次又一次地显示整个数据直到教那个学生的老师数量。任何团体都得到了解决方案！

<?php 

 session_start();

 $value = $_SESSION['student_roll'];

 require('../includes/connect.php');

 $query = "SELECT students.firstname, students.lastname, students.roll, students.semester, students.course, teachers.firstname, teachers.teaching FROM students,teachers WHERE students.roll = $value AND students.semester = teachers.semester";
 $run = mysqli_query($conn,$query);
while($result = mysqli_fetch_array($run)){

    $students_firstname = $result["0"];
    $students_lastname = $result["1"];
    $students_roll = $result["2"];
    $students_semester = $result["3"];
    $students_course = $result["4"];
    $teacher_name = $result["5"];
    $teacher_teaching = $result["6"];
?>

<h2>Name : <?php echo $students_firstname . " " . $students_lastname?></h2>
<h2>Roll : <?php echo $students_roll ?></h2>
<h2>Semester : <?php echo $students_semester ?></h2>
<h2>Course : <?php echo $students_course ?></h2>

<h2>You're enrolled under : <?php echo $teacher_name ?> & studying <?php echo $teacher_teaching ?></h2>


<?php
} ?>

如果我只使用if我就得到了这个

http://i.stack.imgur.com/nAUGu.png

使用while我得到了这个输出。

http://i.stack.imgur.com/ACxWI.png

Answer 1

问题是一个学生有几个老师，所以一个记录不足以容纳所有信息。将查询拆分为两个：

首先，为学生阅读并输出姓名，学期等：

$query = "SELECT firstname, lastname, semester, course FROM students,teachers WHERE students.roll = $value";

然后，查询该学生的所有教师......

$query = "SELECT teachers.firstname, teachers.teaching FROM students,teachers WHERE students.roll = $value AND students.semester = teachers.semester";

...并在while循环中输出信息。

无法在PHP中获取特定记录

1 个答案: