Parse error: syntax error, unexpected '' (T_ENCAPSED_AND_WHITESPACE), expecting identifier (T_STRING) or variable (T_VARIABLE) or number (T_NUM_STRING

<?php
include('dbconnection.php');
$sql="select * from user where id ='.$_REQUEST['id'].' ";
$result = mysql_query( $sql);
if(!$result )
{
  die('Could not enter data: ' . mysql_error());
}