Hay que...vs. Tener que

This site gives you an exact difference

http://www.studyspanish.com/lessons/tenque.htm

Thank you for using the Homework Help Forum. Let's look at each one separately.

hay que = this comes from the verb haber and means "one must" or "it is necessary." It doesn't specify per se "I, you, he, she, we, they" must, but is more impersonal. Example: hay que estudiar = one must study or it is necessary to study.

tiene que = this comes from the verb tener and means "to have to" or "must." The verb tener usually has a specific pronoun (or noun) with it. Ex. Tú tienes que estudiar = you have to study or you must study.

Note that either construction must be followed by an infinitive.