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Commit 96f4396

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Added task 3570
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3570\. Find Books with No Available Copies
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Easy
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Table: `library_books`
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+------------------+---------+
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| Column Name | Type |
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+------------------+---------+
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| book_id | int |
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| title | varchar |
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| author | varchar |
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| genre | varchar |
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| publication_year | int |
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| total_copies | int |
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+------------------+---------+
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book_id is the unique identifier for this table.
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Each row contains information about a book in the library, including the total number of copies owned by the library.
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Table: `borrowing_records`
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+---------------+---------+
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| Column Name | Type |
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|----------------|---------|
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| record_id | int |
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| book_id | int |
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| borrower_name | varchar |
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| borrow_date | date |
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| return_date | date |
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+----------------+---------+
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record_id is the unique identifier for this table.
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Each row represents a borrowing transaction and return_date is NULL if the book is currently borrowed and hasn't been returned yet.
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Write a solution to find **all books** that are **currently borrowed (not returned)** and have **zero copies available** in the library.
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* A book is considered **currently borrowed** if there exists a borrowing record with a **NULL** `return_date`
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Return _the result table ordered by current borrowers in **descending** order, then by book title in **ascending** order._
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The result format is in the following example.
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**Example:**
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**Input:**
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library\_books table:
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+---------+--------------------------+----------------+-----------+------------------+--------------+
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| book_id | Title | Author | Genre | Publication Year | Total Copies |
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|---------|--------------------------|----------------|-----------|------------------|--------------|
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| 1 | The Great Gatsby | F. Scott | Fiction | 1925 | 3 |
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| 2 | To Kill a Mockingbird | Harper Lee | Fiction | 1960 | 3 |
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| 3 | 1984 | George Orwell | Dystopian | 1949 | 1 |
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| 4 | Pride and Prejudice | Jane Austen | Romance | 1813 | 2 |
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| 5 | The Catcher in the Rye | J.D. Salinger | Fiction | 1951 | 1 |
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| 6 | Brave New World | Aldous Huxley | Dystopian | 1932 | 4 |
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+---------+--------------------------+----------------+-----------+------------------+--------------+
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borrowing\_records table:
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+-----------+---------+---------------+-------------+-------------+
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| record_id | book_id | borrower_name | borrow_date | return_date |
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|-----------|---------|---------------|-------------|-------------|
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| 1 | 1 | Alice Smith | 2024年01月15日 | NULL |
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| 2 | 1 | Bob Johnson | 2024年01月20日 | NULL |
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| 3 | 2 | Carol White | 2024年01月10日 | 2024年01月25日 |
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| 4 | 3 | David Brown | 2024年02月01日 | NULL |
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| 5 | 4 | Emma Wilson | 2024年01月05日 | NULL |
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| 6 | 5 | Frank Davis | 2024年01月18日 | 2024年02月10日 |
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| 7 | 1 | Grace Miller | 2024年02月05日 | NULL |
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| 8 | 6 | Henry Taylor | 2024年01月12日 | NULL |
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| 9 | 2 | Ivan Clark | 2024年02月12日 | NULL |
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| 10 | 2 | Jane Adams | 2024年02月15日 | NULL |
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+-----------+---------+---------------+-------------+-------------+
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**Output:**
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+---------+-------------------+----------------+-----------+------------------+-------------------+
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| book_id | Title | Author | Genre | Publication Year | Current Borrowers |
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|---------|-------------------|----------------|-----------|------------------|-------------------|
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| 1 | The Great Gatsby | F. Scott | Fiction | 1925 | 3 |
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| 3 | 1984 | George Orwell | Dystopian | 1949 | 1 |
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+---------+-------------------+----------------+-----------+------------------+-------------------+
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**Explanation:**
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* **The Great Gatsby (book\_id = 1):**
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* Total copies: 3
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* Currently borrowed by Alice Smith, Bob Johnson, and Grace Miller (3 borrowers)
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* Available copies: 3 - 3 = 0
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* Included because available\_copies = 0
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* **1984 (book\_id = 3):**
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* Total copies: 1
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* Currently borrowed by David Brown (1 borrower)
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* Available copies: 1 - 1 = 0
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* Included because available\_copies = 0
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* **Books not included:**
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* To Kill a Mockingbird (book\_id = 2): Total copies = 3, current borrowers = 2, available = 1
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* Pride and Prejudice (book\_id = 4): Total copies = 2, current borrowers = 1, available = 1
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* The Catcher in the Rye (book\_id = 5): Total copies = 1, current borrowers = 0, available = 1
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* Brave New World (book\_id = 6): Total copies = 4, current borrowers = 1, available = 3
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* **Result ordering:**
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* The Great Gatsby appears first with 3 current borrowers
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* 1984 appears second with 1 current borrower
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Output table is ordered by current\_borrowers in descending order, then by book\_title in ascending order.
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# Write your MySQL query statement below
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# #Easy #Database #2025_06_03_Time_512_ms_(100.00%)_Space_0.0_MB_(100.00%)
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SELECT
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book_id,
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MAX(title) AS title,
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MAX(author) AS author,
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MAX(genre) AS genre,
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MAX(publication_year) AS publication_year,
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MAX(total_copies) AS current_borrowers
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FROM (
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SELECT
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book_id,
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title,
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author,
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genre,
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publication_year,
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total_copies,
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total_copies AS total_remain
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FROM library_books
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UNION ALL
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SELECT
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book_id,
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'' AS title,
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'' AS author,
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'' AS genre,
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1000 AS publication_year,
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0 AS total_copies,
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-1 AS total_remain
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FROM borrowing_records
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WHERE return_date IS NULL
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) AS sub
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GROUP BY
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book_id
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HAVING
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SUM(total_remain) = 0
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ORDER BY
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current_borrowers DESC,
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title ASC;
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package g3501_3600.s3570_find_books_with_no_available_copies;
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import static org.hamcrest.CoreMatchers.equalTo;
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import static org.hamcrest.MatcherAssert.assertThat;
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import java.io.BufferedReader;
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import java.io.FileNotFoundException;
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import java.io.FileReader;
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import java.sql.Connection;
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import java.sql.ResultSet;
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import java.sql.SQLException;
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import java.sql.Statement;
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import java.util.stream.Collectors;
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import javax.sql.DataSource;
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import org.junit.jupiter.api.Test;
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import org.zapodot.junit.db.annotations.EmbeddedDatabase;
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import org.zapodot.junit.db.annotations.EmbeddedDatabaseTest;
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import org.zapodot.junit.db.common.CompatibilityMode;
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@EmbeddedDatabaseTest(
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compatibilityMode = CompatibilityMode.MySQL,
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initialSqls =
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"CREATE TABLE library_books(book_id INTEGER, title VARCHAR(255)"
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+ ", author VARCHAR(255), genre VARCHAR(255), publication_year "
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+ "INTEGER, total_copies INTEGER); "
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+ "INSERT INTO library_books (book_id, title, author, genre, "
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+ "publication_year, total_copies) VALUES "
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+ "(1, 'The Great Gatsby', 'F. Scott', 'Fiction', 1925, 3),"
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+ "(2, 'To Kill a Mockingbird', 'Harper Lee', 'Fiction', 1960, 3),"
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+ "(3, '1984', 'George Orwell', 'Dystopian', 1949, 1),"
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+ "(4, 'Pride and Prejudice', 'Jane Austen', 'Romance', 1813, 2),"
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+ "(5, 'The Catcher in the Rye','J.D. Salinger', 'Fiction', 1951, 1),"
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+ "(6, 'Brave New World', 'Aldous Huxley', 'Dystopian', 1932, 4);"
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+ "CREATE TABLE borrowing_records(record_id INTEGER, book_id INTEGER"
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+ ", borrower_name VARCHAR(255), borrow_date DATE, return_date DATE); "
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+ "INSERT INTO borrowing_records(record_id, book_id, borrower_name, "
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+ "borrow_date, return_date) VALUES "
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+ "(1, 1, 'Alice Smith', '2024年01月15日', NULL),"
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+ "(2, 1, 'Bob Johnson', '2024年01月20日', NULL),"
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+ "(3, 2, 'Carol White', '2024年01月10日', '2024年01月25日'),"
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+ "(4, 3, 'David Brown', '2024年02月01日', NULL),"
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+ "(5, 4, 'Emma Wilson', '2024年01月05日', NULL),"
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+ "(6, 5, 'Frank Davis', '2024年01月18日', '2024年02月10日'),"
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+ "(7, 1, 'Grace Miller', '2024年02月05日', NULL),"
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+ "(8, 6, 'Henry Taylor', '2024年01月12日', NULL),"
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+ "(9, 2, 'Ivan Clark', '2024年02月12日', NULL),"
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+ "(10,2, 'Jane Adams', '2024年02月15日', NULL);")
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class MysqlTest {
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@Test
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void testScript(@EmbeddedDatabase DataSource dataSource)
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throws SQLException, FileNotFoundException {
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try (final Connection connection = dataSource.getConnection()) {
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try (final Statement statement = connection.createStatement();
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final ResultSet resultSet =
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statement.executeQuery(
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new BufferedReader(
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new FileReader(
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"src/main/java/g3501_3600/"
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+ "s3570_find_books_with_no_available_copies/"
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+ "script.sql"))
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.lines()
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.collect(Collectors.joining("\n"))
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.replaceAll("#.*?\\r?\\n", ""))) {
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assertThat(resultSet.next(), equalTo(true));
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assertThat(resultSet.getNString(1), equalTo("1"));
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assertThat(resultSet.getNString(2), equalTo("The Great Gatsby"));
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assertThat(resultSet.getNString(3), equalTo("F. Scott"));
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assertThat(resultSet.getNString(4), equalTo("Fiction"));
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assertThat(resultSet.getNString(5), equalTo("1925"));
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assertThat(resultSet.getNString(6), equalTo("3"));
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assertThat(resultSet.next(), equalTo(true));
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assertThat(resultSet.getNString(1), equalTo("3"));
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assertThat(resultSet.getNString(2), equalTo("1984"));
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assertThat(resultSet.getNString(3), equalTo("George Orwell"));
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assertThat(resultSet.getNString(4), equalTo("Dystopian"));
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assertThat(resultSet.getNString(5), equalTo("1949"));
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assertThat(resultSet.getNString(6), equalTo("1"));
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assertThat(resultSet.next(), equalTo(false));
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}
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}
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}
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}

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