Question

I have table ( users )
and I have another table let’s say (books)

users table :

Id | Username

1 :: john

2 :: doe

books table:

id | book_title | user_id(user who own this book)

1 :: book1 :: 2

2 :: book2 :: 2

3 :: book3 :: 2

4 :: book4 :: 1

5 :: book5 :: 1

Now , how can I get list of users and get how many books every user have

like this :

• john ( 2 books )

• doe ( 3 books )

---

I use codeigniter framework ..

thanks in advance 🙂

Answer 1

To answer your second question:

I just had to do this for some of my own analytics:

SELECT users.* , 

   (SELECT COUNT( 1 ) 
    FROM books
    WHERE user_id = users.id) 
    AS  "Number of Books",

   (SELECT COUNT( 1 )
    FROM files
    WHERE user_id = users.id)
    AS  "Number of Files"

FROM users

If you have to do this frequently, you might want to figure out how to do this using multiple joins which are more efficient than subqueries.