at or in?

[mr alfred]

Help me to check whether the book is available in any book store in New York?

or

Help me to check whether the book is available at any book store in New York?

which one is the correct sentence?

Thank You!

[JMurray]

Neither sentence is a question, so the question mark is incorrect. Otherwise, both sentences are fine, although it's quite normal to make "bookstore" one word.

not a teacher

[emsr2d2]

Both prepositions work as long as the corrections JMurray gave are followed too.