Q&A for those interested in the geology, meteorology, oceanography, and environmental sciences
with comment_count as ( select UserId ,count(Id) count_comments from Comments group by UserId ) , post_count as ( select OwnerUserId ,count(a.id) count_posts from Posts a group by OwnerUserId ) select coalesce(a.OwnerUserId, UserId) UserId ,count_posts + count_comments as total_count from post_count a full join comment_count b on a.OwnerUserId = b.UserId