รบกวนผู้รู้ช่วยทีครับ PHP + SQLSrv ในการ query แบบมีเงื่อนไขด้วย datetime แล้ว error ครับ

<?php

	ini_set('display_errors', 1);
	error_reporting(~0);

	$mshost = "soul";
	$msuser = "sa";
	$mspass = "1234";
	$msdb = "att";
  
   $coninfo = array("Database"=>$msdb, "UID"=>$msuser, "PWD"=>$mspass);

   $conn = sqlsrv_connect($mshost, $coninfo);

	if($conn)
	{
		echo "Database Connected.<br>";
	}
	else
	{
		echo "Database Connect Failed.<br>";
	}
?>

<?php
	include "inc/msdatabase.php";

	$dt = date("2014-12-30 22:49:28");

	$stmt = "select CHECKINOUT.USERID as idu,* from CHECKINOUT join USERINFO on CHECKINOUT.USERID = USERINFO.USERID where CHECKTIME = '$dt'";
	$sel = sqlsrv_query($conn, $stmt) or die(sqlsrv_errors());

	while($result = sqlsrv_fetch_array($sel, SQLSRV_FETCH_ASSOC))
	{
		echo $result['CHECKTIME']."<br>";
	}

?>