gozap_api/Admin/login.php

<?php
include_once "../include/DB.php";
$userPhoneNumber="";
$userPassword="";

if (isset($_POST["phonenumber"]) && !empty($_POST["phonenumber"])) {
   $userPhoneNumber=$_POST["phonenumber"];
}

if (isset($_POST["password"]) && !empty($_POST["password"])) {
   $userPassword=$_POST["password"];
}

$sql = "SELECT UserID,
UserName,
PhoneNumber,
IsAdmin,
CreatedAt AS UserCreatedAt,
UpdatedAt AS UserUpdatedAt
FROM user WHERE PhoneNumber='$userPhoneNumber' AND Password='$userPassword'";
$result = $conn->query($sql);

if ($result!== false && $result->num_rows > 0 ) {        
    $listArray = [];
    // output data of each row
    while($row = $result->fetch_assoc()) {
        if ($row["IsAdmin"]==1) { 
            // Declare an array 
            $value = array(
                "UserID"=>(int)$row["UserID"],
                "UserName"=>$row["UserName"],
                "PhoneNumber"=>$row["PhoneNumber"],
                "IsAdmin"=>(int)$row["IsAdmin"],
                "UserCreatedAt"=>$row["UserCreatedAt"],
                "UserUpdatedAt"=>$row["UserUpdatedAt"],
                "Message"=>"Your login successful"
            );
        }else {
            http_response_code(404);
            $value = array(
                "Message"=>"Your login failed, You are not a admin to access",
                "Error"=>"You are not a admin"
            );
        }
        $listArray[]= $value;
    }

    $count = count($listArray);

    if($count==1){
        // Use json_encode() function
        $json = json_encode($listArray[0]);
    }else {
        // Use json_encode() function
        $json = json_encode($listArray);
    }
 
} else {   
  http_response_code(404);
  $errorMesage= $conn->error;
  if ($errorMesage=="") {
    $errorMesage = "User name or password incorrect";
  }
  // Declare an array with error message 
  $value = array(
    "Message"=>"Your login failed",
    "Error"=>$errorMesage
  );
  // Use json_encode() function
  $json = json_encode($value);
}
// Display the output
echo($json);
$conn->close();