Php unable to determine userid availability with jQuery Validate - php

Question

I have a problem with using jQuery validate remote function with php. I try to check the user id with query whether the user id is exist or not. But it alway show user is in used.
Here is my jQuery validate code:
userID: {
required: true,
minlength: 5,
remote : {
url: "checkUserId.php",
type: "post"
}
},
Here is my php checking code:
<?php
include "session.php";
include 'dbConnect.php';
global $conn;
$requestedID = $_POST['userID'];
$query = "SELECT * FROM Users WHERE _userID = '$requestedID'";
$result = sqlsrv_query($conn,$query);
$row_count = sqlsrv_num_rows($result);
if($row_count === false){
echo 'false';
}
else if($row_count >=0){
echo 'true';
}
?>
Anything I did wrong in my query?

Answer 1

Change your if else condition.
if($row_count == 0){
echo 'true';
}else{
echo 'false';
}
true = not exist, false = exist

Answer 2

I had successfully solved it with this code. Thanks for all the support.
Here is my updated code:
<?php
include "session.php";
include 'dbConnect.php';
global $conn;
$requestedID = $_REQUEST['userID'];
$query = "SELECT * FROM Users WHERE _userID = '$requestedID'";
$params = array();
$options = array( "Scrollable" => SQLSRV_CURSOR_KEYSET );
$result = sqlsrv_query($conn,$query , $params, $options);
$row_count = sqlsrv_num_rows($result);
if($row_count >= 1){
echo 'false';
}
else{
echo 'true';
}
?>