Tóm tắt dữ liệu

public class Main {
    public static void main(String[] args) throws SQLException {
        HikariDataSource ds = HikariSetup.createDataSource();
        String query = """
            --  Count the number of reviews and the average rating
            SELECT book_id, ____(*), ____(rating)
            FROM book_reviews
            -- Group reviews by book_id
            ____ ____ ____;
            """;

        try (Connection conn = ds.getConnection();
             PreparedStatement pstmt = conn.prepareStatement(query);
             ResultSet rs = pstmt.executeQuery()) {
            while (rs.next()) {
                System.out.printf("ID: %d, Count: %d, Average: %.0f%n",
                        rs.getInt("book_id"), rs.getInt("count"), rs.getDouble("avg"));
            }
        }
    }
}