can't get 'scope' value from core_config_data table

Question

I need to make an sql sentence where i retrieve records filtered by 'scope' value from core_config_data table. This is the script:

$query = "SELECT * FROM  `core_config_data` WHERE  `scope` = $scope";

I get $scope with this line:

$scope = Mage::getSingleton('adminhtml/config_data')->getScope();

But when i run this, i receive an error saying:

An error occurred while saving this configuration: SQLSTATE[42S22]: Column not found: 1054 Unknown column 'stores' in 'where clause'

When i run the same sql sentence in phpmyadmin, it works fine and it retrieves the correct record, so i don't know what's wrong here.

Thanks for helping