Depends how you define school shooting as well. Click around on https://www.chds.us/sssc/data-map/ . There are numerous incidents like "Teacher killed himself in classroom after school hours" "Shots fired in the evening, no one injured".
Also, if you go into that data a total of 260 Students were fatally wounded by a firearm from 1970 to 2022 during the school day.
If this is accurate, the odds of being fatally shot as a student during school hours is extremely low, about 1 in 10,000,000 over the span of this data collection. Higher odds than winning a powerball jackpot, but, in context, an extremely rare event.
It wouldn't be a stretch to hypothesize that the administrators forcing students through metal detectors, doing active shooter drills, etc, are doing more net harm than the thing that they are attempting to defend against (as a purely utilitarian calculation).
