mssql มีปัญหากับ paging ครับ ใช้ ROW_NUMBER() แล้วไม่ได้ตามที่ต้องการ

$sql = "SELECT   *
FROM (SELECT ROW_NUMBER() OVER(ORDER BY PRODUCT_SKU_OID) rown, * FROM PRODUCT_SKU) t WHERE PRODUCT_NAME like '%$keyword%' ";

$pagesize = "20";
$pagefinal = "0";

		$result = mssql_query($sql) or exit("Err $sql");
		$total = mssql_num_rows($result);
		
		echo "total=$total<br/>";


		$pagetotal = ceil($total/$pagesize);
		
		$page = $_GET[page];
		if (empty($page))
			$page = 1;
		
		$start = ($page-1)*$pagesize;
		$maxp = $start+$pagesize;

		
		$sql.= "and rown BETWEEN $start+1 and $maxpage " ;	
		
		echo "sqlfinal=$sql";

		$result = mssql_query($sql) or exit("Err2 $sql");
		$num = mssql_num_rows($result);