As stated in the comments below the question,
Comments don’t have ratings in WordPress
I went on and inspected the HTML source for one of my posts and figured out which plugin generated the rating based on the CSS class name. I should have known better. The plugin is Tasty Recipes by WP Tasty.
I then looked at my SQL DB and figured out that comment ratings are stored in wp_commentmeta with a key of ERRating:
SELECT * FROM `wp_commentmeta` WHERE meta_key='ERRating'
Here’s a more complete SQL statement that shows how to retrieve the rating:
SELECT c.comment_id,
c.comment_post_id,
c.comment_author,
c.comment_content,
m.meta_key,
m.meta_value
FROM `wp_del201712_comments` AS c
LEFT JOIN wp_del201712_commentmeta m
ON m.comment_id = c.comment_id
WHERE c.comment_post_id = 12066
AND c.comment_approved = '1'
AND m.meta_key = 'ERRating'
Just replace the post ID with yours to see the results.