It talks about pretty much everything - it uses postgresql as a base but talks about theory, db design, sql / nosql / document stores, key-value stores, aggregates, joins, normal forms, etc. all you need to know. your head will explode if you learn everything in a few days

As of interviews: I do not think it particularly focuses on what hiring managers / hr people ask. It gives you general knowledge, but it is not interview focused. You will know enough to pass though.