Joining multiple tables - mysql

Question

I'm rather new to normalizing tables and I'm having some troubles wrapping my head around getting the correct information out of 3 tables. I made an example involving reserving books out of different libraries. I have 3 tables. Books, locations, reservations (listed below):
//SQL query:
$sql =
"SELECT * FROM books
JOIN (location LEFT JOIN reservations ON location.locID = reservations.locID)
ON books.bookID = location.bookID
WHERE location.locID=2
";
and the output I was hoping to achieve if I were to list the books in Campus B:
title |locName |status
Book 1|Campus B|1
Book 2|Campus B|0
Book 3|Campus B|0
Book 4|Campus B|0
Book 5|Campus B|1
For some reason I'm definitely not getting the output I think I should, and I was curious if anyone has some suggestions. I'm sure once I see whats going on I'll understand what I did incorrectly.
table: books
bookID|title
1 | Book 1
2 | Book 2
3 | Book 3
4 | Book 4
5 | Book 5
table: location
locID|locName
1 | campus A
2 | campus B
3 | campus C
table: reservations
bookID|locID|status
1 | 1 | 1
3 | 1 | 1
4 | 1 | 1
1 | 2 | 1
5 | 2 | 1
4 | 3 | 1
5 | 3 | 1

Answer 1

I think this is more in line with what you're looking for:
SELECT *
FROM books b
LEFT JOIN reservations r ON b.bookID = r.bookID
JOIN location l on r.locID = l.locID
WHERE l.locID = 2
This will return a list of the books reserved at the location with locID=2.
In this case I have a LEFT JOIN to preserve your original query, however given your WHERE clause any records with NULL in the location.locID field will not be selected.
Therefore, I could re-write your query with all INNER joins, like so:
SELECT *
FROM books b
JOIN reservations r ON b.bookID = r.bookID
JOIN location l on r.locID = l.locID
WHERE l.locID = 2
Other queries that you might find interesting:
Get ALL books, regardless of whether or not they are reserved anywhere:
SELECT *
FROM books b
LEFT JOIN reservations r ON b.bookID = r.bookID
JOIN location l on r.locID = l.locID
Get ALL locations, regardless of whether or not there are books reserved there:
SELECT *
FROM books b
JOIN reservations r ON b.bookID = r.bookID
RIGHT JOIN location l on r.locID = l.locID
Get ALL books and ALL locations:
SELECT *
FROM books b
LEFT JOIN reservations r ON b.bookID = r.bookID
RIGHT JOIN location l on r.locID = l.locID

Answer 2

SELECT
books.title
, location.locName
, IFNULL(reservations.status, 0) status
FROM
books
JOIN location
LEFT JOIN reservations ON (
location.locID = reservations.locID
AND books.bookID = location.bookID
)
WHERE location.locID = 2