I remember one shooting at school in the fifties. A guy brought his shotgun to Massapequa HS and killed some other guy over a girl. The teacher who disarmed him was Alex Baldwin Sr.
Yes, I remember at least a couple of those kinds of shootings as well.
But I'm talking about a kid just showing up and indiscriminately shooting people for no reason. Two guys having a beef with each other - yes, high school kids killing people just for fun - no.