english question??

STUDY AT...usually means a small place (such as, school)

STUDY IN... usually means in a larger place (such as, Canada)

I study at this school.
I study in XXX school.

There are big difference between this.
at is for the place.
in is for the school's name

通常會用at

You should use in
For example, Today, I stayed in the school for lunch.
Beijing is located in China