CONCAT statement

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
11 53

Author:
author_id author_name
50 John
51 Mike
52 Lisa
53 Rachel

I want to make a select statement which brings:

book_id Authors
10 John, Mike, Lisa
11 Rachel


Please HELP!!!

Code:

---

SELECT wrote.book_id, GROUP_CONCAT(author.author_name)
FROM author, wrote
WHERE author.author_id=wrote.author_id
GROUP BY wrote.book_id

---

This generates:

Code:

---

book_id        GROUP_CONCAT(author.author_name)

10        John,Mike,Lisa
11        Rachel

---

This helps to consolidate the values like you were asking instead of the following where each row with a different name is listed one at a time each with its own row.

Code:

---

SELECT wrote.book_id, author.author_name
FROM author, wrote
WHERE author.author_id=wrote.author_id

---

which produces:

Code:

---

book_id        author_name

10        John
10        Mike
10        Lisa
11        Rachel

---

I know this is a late response.

Further reading:

GROUP BY
GROUP_CONCAT()