How to group together students who attend multiple schools in MySQL?

I have a table composed simply of student and school and I need to reduce this table to just those students who applied to both PSU and MIT, which would be Amy and Helen. So here's what the before and after would look like: Before: student school Amy PSU Amy MIT Bob MIT Fay PSU Jay PSU Irene PSU Helen PSU Helen MIT After: student school Amy PSU Amy MIT Helen PSU Helen MIT Any general direction I could be pointed in? I'm fairly new to SQL so this may be trivial as I'm not aware of all SQL operations. I believe this can be done with GROUP BY but I'm not sure how. Thanks