It has become obvious to me that SQL syntax is a little different within drupal.
After some fiddling around I am getting the hang of it, but I haven't been able to use wildcards succesfully.
$sql = 'SELECT name Nombre, mail Email FROM users WHERE status = 1 AND mail LIKE ('%@hotmail%') LIMIT 25';
Do you have any suggestion? I haven't been able to find (or I might be looking in the wrong places) for Drupal documentation regarding wildcards within $page_content
in a module.