通过php上的文本字段为用户提供数据？ [关闭]

I'm tryig to create a text input on my page to be able to receive a username which is on my database and return another information of himself, how can i do it? For example entering a name and returning his telephone number. i have just no idea how to start. Thanks

Here's the working code. But learn the basics first.

index.html

<!DOCTYPE html>
<html>
<head>
    <title>Index page</title>
</head>

<body>

<form method="POST" action="retrieve.php">

    Enter your name : <input type="text" name='username'><br><br>
    <input type="submit" name="submit">

</form>

</body>
</html>

retrieve.php

<?php

//Database connection
$connection = mysqli_connect("localhost","username","password","database_name");

if (isset($_POST['submit'])) {

    $uname = $_POST['username'];

    // sql query and user is the table name
    $query = "SELECT * FROM `user` WHERE user_name='$uname'";

    // query to execute
    $result = mysqli_query($connection,$query);

    if (!$result) {
        echo "fails";
    }


    while($row = mysqli_fetch_array($result)) {

        $telephone_no = $row['phoneno'];
        $country_name = $row['country'];

        echo "Your results for name - " . $uname;
        echo "<br><br>";

        echo "Telelephone is : " . $telephone_no;
        echo "<br>";
        echo "Country name is : " . $country_name;   
    }  
}
?>

Database structure : (User table)

enter image description here

To test the code, insert a person details in PHPMyadmin insert tab.(Leave id alone as it was set to an auto-increment).

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          <?php



          if(isset($_POST['username']){
                   try{


     $dbh = new PDO("mysql:dbname=Amor;host=127.0.0.1", 
                "Javier",     "your_password");
            $sql = "SELECT name, phone, address FROM people_table  

                 WHERE                                                                                                                 username=:username";
                     $res = $dbh->prepare($sql);
         $res->bindParam('username', $_POST['username'], PDO::PARAM_STRING);
                        $res->exec();


                 $row = $res->fetchAll(PDO::FETCH_ASSOC);


         print_r($row);
                //Sorry mate I'm feeling lazy. You can take over from here
        }
        ?>


         **//html code here**

       <form action="" method="GET>
      <input type="text" name="username">
      <input type="submit" value="Search">
              </form>