PHP获取mysql数据并使用ajax返回javascript

I'm reading the values of my MySql-Databasetable with php like this:

  <?php

header("Access-Control-Allow-Origin: *");
header("Access-Control-Allow-Methods: PUT, GET, POST");
header("Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept");

$servername = "localhost";
$username = "wsl_home";
$password = "wsl";
$dbname = "wsl_home";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 

if(isset($_POST['functionname']) == 'getDrinks') {
    $sql = "SELECT ID, Drinkname FROM drinks";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // output data of each row
    while($row = $result->fetch_assoc()) {
        echo "ID: " . $row["ID"]. " - Name: " . $row["Drinkname"]. "<br>";
        return $row;
    }
} else {
    echo "0 results";
}
}
?>

This works and i get the values as expected. Now I want to return them to my javascript using ajax to call the php function:

   jQuery.ajax({
            type: "POST",
            url: 'drinks.php',
            dataType: 'json',
            data: {functionname: 'getDrinks', arguments: [1, 2]},
            success: function (obj, textstatus) {
                          if( !('error' in obj) ) {
                              console.log("hi " + obj);
                              yourVariable = obj.result;
                          }
                          else {
                              console.log(obj.error);
                          }
                    }
        });

But I get no output in the success function. Does somebody know how to accomplish this task?