php数据库连接异常

php数据库连接错误
有代码如下：

$catid=intval($_REQUEST['catid']);
$sql_store = 'SELECT * FROM ecm_gcategory Where cate_id=$catid ORDER BY cate_id';
$my_category= DB::fetch_all($sql_store);

运行报如下错误：
SELECT * FROM ecm_gcategory Where cate_id=$catid ORDER BY cate_id


怎么解决哟？请高人指点！
------解决思路----------------------
$sql_store = "SELECT * FROM ecm_gcategory Where cate_id=$catid ORDER BY cate_id";
双引号！
------解决思路----------------------
单引号里面的变量不能被解析，需用双引号括起来。或者改成下面这样：
$sql_store = 'SELECT * FROM ecm_gcategory Where cate_id='.$catid.' ORDER BY cate_id';