Looking on the internet deeply has found these results:

I study in is the most popular phrase on the web.

I study at 1372,000 results on the web	I study in 1488,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
I been here three month. I study at the university. I study at the mall all the time. I study at school's Maud... at Maud's school! I study at a university in Boston. Can I study at Hela's tonight?	meaning human bodies, animal bodies I'm a historian by training, and what I study in that case is the way that people have dealt with anatomy A phase I study in 18 obese patients with type 2 diabetes mellitus (BMI between 35 and 40 kg/ m2) with insulin glulisine and insulin lispro [90% CI: I study in Gagarin Space School. how they dealt with bodily fluids, concepts of bodies; how have they thought about bodies. I met her when I study in New York.

I study at

1372,000 results on the web

I study in

1488,000 results on the web

More popular!

meaning human bodies, animal bodies
I'm a historian by training, and what I study in that case is the way that people have dealt with anatomy
A phase I study in 18 obese patients with type 2 diabetes mellitus (BMI between 35 and 40 kg/ m2) with insulin glulisine and insulin lispro [90% CI:
I study in Gagarin Space School.
how they dealt with bodily fluids, concepts of bodies; how have they thought about bodies.
I met her when I study in New York.