Q&A for anime and manga fans
with posts_no_comments as ( select count(a.Id) no_comment_total from Posts a left join Comments b on a.Id = PostId where b.PostId is null ) , total_posts as ( select count(a.Id) total_posts from Posts a ) SELECT (no_comment_total * 100.0 / total_posts) AS no_comment_percentage FROM posts_no_comments CROSS JOIN total_posts