php查询结果的分页显示，点击下一页时不能记寓所查询的东西，只要点击下页时，显示出来的结果却是全部数据

// 获取select值
$select_value = isset($_GET['select']) ? $_GET['select'] : '';
//echo $select_value;

//执行查询SQL
if($select_value==""){
	_page("SELECT o_id FROM t_order",5);
	$_result= mysql_query("SELECT * FROM t_order  ORDER BY createtime DESC LIMIT $_pagenum,$_pagesize");
}
if($select_value=="option1"){
	_page("SELECT o_id FROM t_order where status=0",4);
	$_result1= mysql_query("SELECT * FROM t_order where status=0 ORDER BY createtime DESC LIMIT $_pagenum,$_pagesize");
	//echo _num_rows($_result);
	
}
if($select_value=="option2"){
	_page("SELECT o_id FROM t_order where status=1",20);
	$_result= mysql_query("SELECT * FROM t_order where status=1 ORDER BY createtime DESC LIMIT $_pagenum,$_pagesize");
}
if($select_value=="option3"){
	_page("SELECT o_id FROM t_order where status=2",20);
    $_result= mysql_query("SELECT * FROM t_order where status=2 ORDER BY createtime DESC LIMIT $_pagenum,$_pagesize");
}[code=php]