Macros with SQL?

I am trying to filter out locations and devices which are currently under scheduled maintenance from showing up in the alert list. I have managed to cook a query which returns a list of currently active schedules, given a device_id.
(Currently disregarding schedules mapped to a Group and recurring schedules)

The macro documentation indicates that SQL in macros is possible, but does not provide a complete example for this. Anyone care to lend a hand?

    SELECT alert_schedule.schedule_id 
    FROM alert_schedule,alert_schedulables 
    WHERE alert_schedule.schedule_id=alert_schedulables.schedule_id 
      AND now() BETWEEN alert_schedule.start AND alert_schedule.end
      AND (
        alert_schedulables.alert_schedulable_type LIKE 'device' AND alert_schedulable_id = ?
        alert_schedulables.alert_schedulable_type LIKE 'location' AND alert_schedulable_id=(SELECT location_id FROM devices WHERE devices.device_id = ?)