Sending Alerts Based on Threshold

I am building an app wherein user can create an alert based on current value of average or sum of table column. For example if SUM of column A is < 100 a notification should be sent to receipients.
User can add query and condition dynamically. Is there any existing sample or gem that constantly checks for database value and sends notification for alert . I also what it to be snoozable so it wont spam notification if value does not move for a day or two