php - MySQL Join 和 Echo 结果

Question

我试图做一个简单的 JOIN，当尝试加载页面时它是空白的。当我输入查询时。我试图让它打印查询。我知道如何打印结果但是在打印连接时遇到了问题。

SELECT user.name, course.name
    FROM `user`
    INNER JOIN `course` on user.course = course.id;

在我在 PHPmyAdmin 上的 SQL 中它返回

NAME        Course
Alice       HTML5
Bob         HTML5
Caroline    CSS3

---

<?php
$con=mysqli_connect("URL,"USERNAME","PASS","DB");
// Check connection
if (mysqli_connect_errno()) {
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

$result = mysqli_query($con,"SELECT user.name, course.name
FROM `user`
INNER JOIN `course` on user.course = course.id;");

while($row = mysqli_fetch_array($result)) {
  echo $row['user.name'] . " " . $row['course.name'];
  echo "<br>";
}

mysqli_close($con);
?>

感谢您的任何见解...

Answer 1

你不需要使用 $row['user.name'] 它应该是 $row['name'] 但因为你有两列相同name as name 所以你必须改变将它们分配给其他变量。

[提示]:检查新查询和 while 循环中的 echo。 请进行以下更改:

 <?php
    $con=mysqli_connect("HOST","USERNAME","PASS","DB");
    // Check connection
    if (mysqli_connect_errno()) {
        echo "Failed to connect to MySQL: " . mysqli_connect_error();
    }

    $result = mysqli_query($con,"SELECT user.name as username, course.name as coursename
    FROM `user`
    INNER JOIN `course` on user.course = course.id;");

    while($row = mysqli_fetch_array($result)) {
        echo $row['username'] . " " . $row['coursename'];
        echo "<br>";
    }

    mysqli_close($con);
?>