Watch 10 video solutions for Books with NULL Ratings, a easy level problem involving Database. This walkthrough by Nicholas Renotte has 800,387 views views. Want to try solving it yourself? Practice on FleetCode or read the detailed text solution.
Table: books
+----------------+---------+ | Column Name | Type | +----------------+---------+ | book_id | int | | title | varchar | | author | varchar | | published_year | int | | rating | decimal | +----------------+---------+ book_id is the unique key for this table. Each row of this table contains information about a book including its unique ID, title, author, publication year, and rating. rating can be NULL, indicating that the book hasn't been rated yet.
Write a solution to find all books that have not been rated yet (i.e., have a NULL rating).
Return the result table ordered by book_id in ascending order.
The result format is in the following example.
Example:
Input:
books table:
+---------+------------------------+------------------+----------------+--------+ | book_id | title | author | published_year | rating | +---------+------------------------+------------------+----------------+--------+ | 1 | The Great Gatsby | F. Scott | 1925 | 4.5 | | 2 | To Kill a Mockingbird | Harper Lee | 1960 | NULL | | 3 | Pride and Prejudice | Jane Austen | 1813 | 4.8 | | 4 | The Catcher in the Rye | J.D. Salinger | 1951 | NULL | | 5 | Animal Farm | George Orwell | 1945 | 4.2 | | 6 | Lord of the Flies | William Golding | 1954 | NULL | +---------+------------------------+------------------+----------------+--------+
Output:
+---------+------------------------+------------------+----------------+ | book_id | title | author | published_year | +---------+------------------------+------------------+----------------+ | 2 | To Kill a Mockingbird | Harper Lee | 1960 | | 4 | The Catcher in the Rye | J.D. Salinger | 1951 | | 6 | Lord of the Flies | William Golding | 1954 | +---------+------------------------+------------------+----------------+
Explanation:
