From 29ab3ac31b9188c62b004ac193d08c98ee06a379 Mon Sep 17 00:00:00 2001 From: ivanbyone Date: Sat, 19 Jul 2025 18:59:36 +0300 Subject: [PATCH] task: #3570 & All fremium easy completed --- README.md | 1 + ...0. Find Books with No Available Copies.sql | 59 +++++++++++++++++++ 2 files changed, 60 insertions(+) create mode 100644 leetcode/easy/3570. Find Books with No Available Copies.sql diff --git a/README.md b/README.md index c423128..8257781 100644 --- a/README.md +++ b/README.md @@ -159,6 +159,7 @@ Useful for preparing for technical interviews and improving your SQL skills. - [2356. Number of Unique Subjects Taught by Each Teacher](./leetcode/easy/2356.%20Number%20of%20Unique%20Subjects%20Taught%20by%20Each%20Teacher.sql) - [3436. Find Valid Emails](./leetcode/easy/3436.%20Find%20Valid%20Emails.sql) - [3465. Find Products with Valid Serial Numbers](./leetcode/easy/3465.%20Find%20Products%20with%20Valid%20Serial%20Numbers.sql) + - [3570. Find Books with No Available Copies](./leetcode/easy/3570.%20Find%20Books%20with%20No%20Available%20Copies.sql) 2. [Medium](./leetcode/medium/) - [176. Second Highest Salary](./leetcode/medium/176.%20Second%20Highest%20Salary.sql) - [180. Consecutive Numbers](./leetcode/medium/180.%20Consecutive%20Numbers.sql) diff --git a/leetcode/easy/3570. Find Books with No Available Copies.sql b/leetcode/easy/3570. Find Books with No Available Copies.sql new file mode 100644 index 0000000..83b528b --- /dev/null +++ b/leetcode/easy/3570. Find Books with No Available Copies.sql @@ -0,0 +1,59 @@ +/* +Question 3570. Find Books with No Available Copies +Link: https://leetcode.com/problems/find-books-with-no-available-copies/description/?envType=problem-list-v2&envId=database + +Table: library_books + ++------------------+---------+ +| Column Name | Type | ++------------------+---------+ +| book_id | int | +| title | varchar | +| author | varchar | +| genre | varchar | +| publication_year | int | +| total_copies | int | ++------------------+---------+ +book_id is the unique identifier for this table. +Each row contains information about a book in the library, including the total number of copies owned by the library. +Table: borrowing_records + ++---------------+---------+ +| Column Name | Type | ++---------------+---------+ +| record_id | int | +| book_id | int | +| borrower_name | varchar | +| borrow_date | date | +| return_date | date | ++---------------+---------+ +record_id is the unique identifier for this table. +Each row represents a borrowing transaction and return_date is NULL if the book is currently borrowed and hasn't been returned yet. +Write a solution to find all books that are currently borrowed (not returned) and have zero copies available in the library. + +A book is considered currently borrowed if there exists a borrowing record with a NULL return_date +Return the result table ordered by current borrowers in descending order, then by book title in ascending order. +*/ + +WITH br AS ( + SELECT + book_id, + COUNT(book_id) AS current_borrowers + FROM borrowing_records + WHERE return_date IS NULL + GROUP BY book_id +) + +SELECT + lb.book_id, + lb.title, + lb.author, + lb.genre, + lb.publication_year, + br.current_borrowers +FROM library_books AS lb +INNER JOIN + br + ON lb.book_id = br.book_id +WHERE (lb.total_copies - br.current_borrowers) = 0 +ORDER BY br.current_borrowers DESC, lb.title ASC pFad - Phonifier reborn

Pfad - The Proxy pFad of © 2024 Garber Painting. All rights reserved.

Note: This service is not intended for secure transactions such as banking, social media, email, or purchasing. Use at your own risk. We assume no liability whatsoever for broken pages.

Alternative Proxies:

Alternative Proxy

pFad Proxy

pFad v3 Proxy

pFad v4 Proxy