How many books fall into each category?
SELECT category ,  count(*) FROM book_club GROUP BY category
SELECT category ,  count(*) FROM book_club GROUP BY category
[{'Category': 'Gay M/SF', 'count(*)': 5}, {'Category': 'Gay SF/F', 'count(*)': 2}, {'Category': 'Lesb. M/SF', 'count(*)': 5}]