我正在创建一个图书标签系统，并尝试调用所有具有相同标签的图书。我的查询只显示第一本书，而不是下面任何一本具有相同标签的书。
这是数据库的books表

drop table if exists books;

      create table books (
      isbn_13 varchar (13) primary key,
      title varchar (100),
      author varchar (80),
      publish_date date,
      price decimal (6,2),
      content bytea
    );

以下是数据库的book\u tags表：

CREATE TABLE book_tags
    (
        isbn_13 character varying(13) NOT NULL,
        tag_names character varying(100) NOT NULL,
        CONSTRAINT book_tags_pkey PRIMARY KEY (isbn_13, tag_names),
        CONSTRAINT book_tags_isbn_13_fkey FOREIGN KEY (isbn_13)
            REFERENCES public.books (isbn_13) MATCH SIMPLE
            ON UPDATE NO ACTION
            ON DELETE NO ACTION
    )

下面是调用查询的booktagdaoimpl文件：

public List<Book> getBooksByTag(String tag) {
    List<Book> books = new ArrayList<>();

    try {
        connection = DAOUtilities.getConnection();
        String sql = "SELECT * FROM books INNER JOIN BOOK_TAGS ON tag_names=?";
        stmt = connection.prepareStatement(sql);

        stmt.setString(1, tag);

        ResultSet rs = stmt.executeQuery();

        if (rs.next()) {
            Book book = new Book();

            book.setIsbn13(rs.getString("isbn_13"));
            book.setAuthor(rs.getString("author"));
            book.setTitle(rs.getString("title"));
            book.setPublishDate(rs.getDate("publish_date").toLocalDate());
            book.setPrice(rs.getDouble("price"));
            book.setContent(rs.getBytes("content"));    

            books.add(book);
        }
        System.out.println("seeing if it will pull multiple books from one tag" + books);

    } catch (SQLException e) {
        e.printStackTrace();
    } finally {
        closeResources();
    }

    return books;
}