Q&A about the site for enthusiasts and power users of Windows Phone OS
-- Most popular StackOverflow tags in May 2020
-- What columns to display finally
-- Columns PostId and TagName appears only in Tags table so there is no
-- need to indicate from which table they comes.
select count(PostId) as Rate, TagName
-- Which tables to use
-- Tags - tags characterization
-- PostTags - match Post ids with Tag ids
-- Posts - post characterization
from Tags, PostTags, Posts
where Posts.Id = PostTags.PostId
and Posts.CreationDate < '2020-06-01'
and Posts.CreationDate > '2020-05-01'
group by TagName