How to set the time of evaluation of a daily evaluated alert


I have created a panel with a complicated and time-consuming request.
To not overload my PostgreSQL database with many request I want my alert to be evaluated every 12 hours for example.
The point is I would like it to be evaluated in the morning at 6 am. So when we come to work, we have fresh data and can know if the alert went off during the night.

Do you know if that’s possible and if my approach to the issue is correct ?