Reputation: 55
I am making a library database and I am having a problem in one place. I need to find most popular borrowed book. I have these tables.
--Books-- --BookReader-- --Readers--
book_id book_id reader_id
reader_id
FOR EXAMPLE DATA IN TABLE BookReader;
----BookReader---
reader_id book_id
1 | 2
1 | 3
3 | 2
I think I need to count every book_id in BookReader which is equal(2, 3 and so on) and than find that max number.
I can't write the SQL query to find most popular borrowed book(bookId)
?
Upvotes: 3
Views: 448
Reputation: 2050
select book_id,count(book_id) as buys
from BookReader
group by book_id
order by buys desc
limit 1
Here is the SQLFiddle
Upvotes: 1