从数据库中读取单个值并将其保存在变量中

Question

我的数据库中有一个小表，看起来像这样：

----------------------
id | name      | value
----------------------
1  | test.flag | 0
----------------------
2  | username  | franz
----------------------

我只是尝试读取的值test.flag并将结果存储在变量中。

<?php

    $servername = "127.0.0.1";
    $username   = "test";
    $password   = "test123";
    $dbname     = "testdb";

    $conn = mysqli_connect($servername, $username, $password, $dbname);

    if (!$conn)
    { 
        die("Connection to database failed with error#: " . mysqli_connect_error()); 
    }   

    $sql = "SELECT value FROM mytable WHERE name='test.flag';";

    $result = mysqli_query($conn, $sql);
    echo "<p>".$result."</p><br>";

    if (mysqli_query($conn, $sql))
    {
        echo "<p>Sucessfully</p><br>";
    } else {
        echo "Error: " . $sql . "<br>" . mysqli_error($conn);
    }

    echo "<p>".$sql."</p><br>";
?>

但是执行此script.php文件后，它将加载空白页。

Answer 1

您需要先获取该行，然后再获取echo它。

$result = mysqli_query($conn, $sql);
$row = mysqli_fetch_assoc($result);
echo "Result: " . $row['value'];