Php Webservices:从MySQL获取多个记录并在JSON数组中对其进行编码

I am newbie to PHP webservices using MySQL. I follow this tutorial. I created one table -> loan_applications using phpmyadmin. Currenlty I have 3 records in table related to id 1. I would like to retrive all 3 records and would like to encode it in json.

I tried multiple way and tried googling but unable to get proper json array in response. Here is my get_applications_list.php

<?php

require_once 'include/DB_Functions.php';
$db = new DB_Functions();

// json response array
$response = array();

if (isset($_GET['id'])) {

    // receiving the post params
    $id = $_GET['id'];

    $applications = $db -> getApplicationsList($id);
    if ($applications) {
        // got applications successfully
        $response["status"] = 0;
        $response["id"] = $applications["id"];
        $response["application_id"] = $applications["application_id"];
        $response["requested_amount"] = $applications["requested_amount"];
        $response["interest_per_day"] = $applications["interest_per_day"];  
        $response["gst"] = $applications["gst"];    
        $response["tenure"] = $applications["tenure"];  
        $response["processing_fees"] = $applications["processing_fees"];    
        $response["amount_user_get"] = $applications["amount_user_get"];
        $response["amount_user_pay"] = $applications["amount_user_pay"];
        $response["application_latitude"] = $applications["application_latitude"];
        $response["application_longitude"] = $applications["application_longitude"];
        $response["application_status"] = $applications["application_status"];      
        $response["created_at"] = $applications["created_at"];  
        $response["updated_at"] = $applications["updated_at"];          
        $response["message"] = "Applications details fetched successfully";

        echo json_encode($response);
    } else {
        // applications failed to store
        $response["status"] = 1;
        $response["message"] = "Unknown error occurred in getting details!";
        echo json_encode($response);
    }       
} else {
    // receiving the post params
    $response["status"] = 2;
    $response["message"] = "Required parameters is missing!";
    echo json_encode($response);
}
?>  

Here is my DB_Functions.php

<?php

class DB_Functions {

private $conn;

// constructor
function __construct() {
    require_once 'DB_Connect.php';
    // connecting to database
    $db = new Db_Connect();
    $this->conn = $db->connect();
}

// destructor
function __destruct() {

}     
public function getApplicationsList($id){
    $stmt = $this->conn->prepare("SELECT * FROM loan_applications WHERE id = ?");
    $stmt->bind_param("s", $id);
    $stmt->execute();
    $applications = $stmt->get_result()->fetch_assoc();
    $stmt->close();

    if($applications){
        return $applications;
    }else {
        return false;
    }
}
}
?>   

Here is response which I am getting :

{"status":0,"id":1,"application_id":1,"requested_amount":5000,"interest_per_day":"0.50","gst":18,"tenure":28,"processing_fees":"5.00","amount_user_get":4705,"amount_user_pay":5700,"application_latitude":"9.999999999","application_longitude":"9.999999999","application_status":1,"created_at":"2018-10-10 21:45:17","updated_at":"0000-00-00 00:00:00","message":"Applications details fetched successfully"}  

I am getting only one record but i need all 3 record which associated with id 1. I tried lot but unable to get.

So multiple problems here

1 - Although unsure but Currenlty I have 3 records in table related to id 1 seems incorrect statement. If id is primary key, you cannot have 3 records against one id

2 - $stmt->get_result()->fetch_assoc(); will always return one row, to get multiple rows or collection of rows you will need to do it like following

if ($result = $mysqli->query($query)) {

    /* fetch associative array */
    while ($row = $result->fetch_assoc()) {
        printf ("%s (%s)
", $row["Name"], $row["CountryCode"]);
    }

    /* free result set */
    $result->free();
}

3 - Its quite clear from following code that you are actually sending only one row back

if ($applications) {
        // got applications successfully
        $response["status"] = 0;
        $response["id"] = $applications["id"];
        $response["application_id"] = $applications["application_id"];
        $response["requested_amount"] = $applications["requested_amount"];
        $response["interest_per_day"] = $applications["interest_per_day"];  
        $response["gst"] = $applications["gst"];    
        $response["tenure"] = $applications["tenure"];  
        $response["processing_fees"] = $applications["processing_fees"];    
        $response["amount_user_get"] = $applications["amount_user_get"];
        $response["amount_user_pay"] = $applications["amount_user_pay"];
        $response["application_latitude"] = $applications["application_latitude"];
        $response["application_longitude"] = $applications["application_longitude"];
        $response["application_status"] = $applications["application_status"];      
        $response["created_at"] = $applications["created_at"];  
        $response["updated_at"] = $applications["updated_at"];          
        $response["message"] = "Applications details fetched successfully";

        echo json_encode($response);
    }

You should do it like this

$applications = getAllApplications(); //returns array of applications
$response['applications'] = $applications; // if they keys you want to send and database fields are same you don't need to set them separately
return json_encode($response);