Recap - Books

Available tables and columns:

• <strong>books</strong>: <strong>book</strong>, <strong>page</strong>, <strong>words</strong>

Books have many pages and each page has a lot of words.

In this challenge, we'll calculate cumulative metrics about these books up to each page. Follow these steps:

1. First, calculate the following cumulative aggregations for each book up to each page:
   • Total words (total_words)
   • Maximum words (max_words)
   • Minimum words (min_words)
   • Average words (avg_words)
2. Then, for each page within a book, calculate the ratio: (avg_words - min_words)/(total_words - min_words)
3. Finally, for each book:
   • Densely rank the pages based on this ratio in ascending order (call this column ratio_rank)
   • Order the results first by book and then by ratio_rank

Note: All aggregations (total, max, min, avg) should be cumulative, meaning they should consider all pages up to and including the current page for each book.