mySQL在循環代碼時不起作用它總是回顯“它失敗了”？

Question

當我運行代碼時，它只顯示說它失敗的回聲，我認為沒有丟失的括號或引號

<?php

$link = mysqli_connect("localhost", "id1242269_sql", "pass", "id1242269_sql");
if (mysqli_connect_error()) {
     die("Could not connect to database");
} 

$query = "SELECT * FROM users";
if ($result=mysqli_query($link, $query)) {
    while ($row = mysqli_fetch_array($result)) {
        print_r($row);
    }
} else {
    echo "it failed";
}
?>

Answer 1

這就是mysqli_error（）派上用場的地方。

if ($result=mysqli_query($link, $query)) {
    while ($row = mysqli_fetch_array($result)) {
        print_r($row);
    }
} else {
    printf("Errormessage: %s\n", mysqli_error($link)); // Print error message
}

Answer 2

$link = mysqli_connect("localhost", "id1242269_sql", "pass", "id1242269_sql");

我是新手，但在我的作業中我們也使用了“新”：

$link = new mysqli_connect("localhost", "id1242269_sql", "pass", "id1242269_sql");

Answer 3

問題在於：

$link = mysqli_connect("localhost", "id1242269_sql", "pass", "id1242269_sql");

對我來說工作得很好：

$link = mysqli_connect("localhost", "root", "", "testDb");

我的結果：