I got stuck with this statement.

I have two tables:

Author: author_id, author_name
Wrote: book_id, author id

I want to get book_id with all its authors in one field, concatenating all the authors' names.

For instance, let's suppose we have

Wrote:
book_id author_id
10 50
10 51
10 52

Author:
author_id author_name
50 John
51 Mike
52 Lisa


I want to make a select statement which brings:

book_id Authors
10 John, Mike, Lisa



Please HELP!!!