Question

I have a table like: called BOOKS

+------+-------------------+---------------+
| id   |  book_title       |  author       |
+------+-------------------+---------------+
| 1    |  learning mysql   |  1234 12      |
+------+-------------------+---------------+
| 2    |  learning php     |  125 50       |
+------+-------------------+---------------+

And i want a VIEW from BOOKS and AUTHOR:

+------+-------------------+  
| id   |  author           |
+------+-------------------+
| 12   |  JOHN             |
+------+-------------------+
| 50   |  PAUL             |
+------+-------------------+
| 125  |  CHRISTOPHER      |
+------+-------------------+
| 1234 |  PATRICK          |
+------+-------------------+

So that i can have a VIEW which i should be something like the table which is below but should show instead of author id author name from tabel AUTHOR.

+------+-------------------+-----------------------------------+
| id   |  book_title       |  author                           |
+------+-------------------+-----------------------------------+
| 1    |  learning mysql   |  PATRICK                          |
+------+-------------------+-----------------------------------+
| 1    |  learning mysql   |  CHRISTOPHER                      |
+------+-------------------+-----------------------------------+
| 2    |  learning php     |  JOHN                             |
+------+-------------------+-----------------------------------+
| 2    |  learning php     |  PAUL                             |
+------+-------------------+-----------------------------------+

Answer 1

Your database design is wrong. books.author should be INT and contain foreign key to author.id. Table author should contain name VARCHAR(255) (or two columns referencing to author_name, I’m still not sure whether you have two authors or you split name into 2 entries).

So correct design would be:

BOOKS (
  id INT,
  book_title VARCHAR(255),
  author INT, -- only if each book has just one author
  PRIMARY KEY (id)
)

AUTHOR (
  id INT,
  name VARCHAR(255),
  first_name_id INT, -- If you want to split names into more columns
  PRIMARY KEY (id)
)

-- If you need more authors for one book
-- you maybe should keep original (primary) author id
BOOK_AUTHOR (
  book_id INT,
  author_id INT,
  PRIMARY KEY (book_id, author_id)
);

Than you may select data with:

SELECT BOOKS.id, BOOKS.book_title, AUTHOR.name AS author
FROM BOOKS
-- Study difference between left and inner joins
INNER JOIN AUTHOR on AUTHOR.id = BOOKS.author

And if you need to have more authors for one book:

SELECT BOOKS.id, BOOKS.book_title, AUTHOR.name AS author
FROM BOOKS
LEFT JOIN BOOK_AUTHOR on BOOK_AUTHOR.book_id = BOOKS.id
LEFT JOIN AUTHOR on AUTHOR.id = BOOK_AUTHOR.author_id

And you may need to output authors as Wolfgang Goethe; Oscar Wilde, than you can use GROUP_CONCAT:

SELECT BOOKS.id, BOOKS.book_title,
       GROUP_CONCAT( AUTHOR.name SEPARATOR '; ') AS author
FROM BOOKS
LEFT JOIN BOOK_AUTHOR on BOOK_AUTHOR.book_id = BOOKS.id
LEFT JOIN AUTHOR on AUTHOR.id = BOOK_AUTHOR.author_id
GROUP BY BOOKS.id