I have the same book as you have.
I have the same book that you have.
In Korea, we learn that the same…as and the same…that have different meanings. Teachers or grammar books say that the first example sentence means the book is not the same one but the same kind of that book or one of the same books in the bookstores, while the second means the book is the very book you have.
Swan, however, explains in his book Practical English Usage that there is no difference in meaning between the two cases.
Who is correct?
Best Answer
Many English speakers don't mind the ambiguity that arises in this situation. For example, in the following sentence, the speaker is merely saying that their briefcases are the same design, maker, etc (like the books in the bookstore in your example):
However, those of us who do would probably modify the sentence
into either
Or more likely
The former sentence implies sharing - just like it would is Korea, whereas the latter sentence implies that the books are separate, but the same book (again, like your example - but notice that I am ok saying the same to describe it).
To sum it all up, same as and same that do have different meanings, but most English speakers do not differentiate the two.