Update database counts in Vanilla.

counts.sql

-- Count discussions.
update GDN_Category c
set CountDiscussions = (select coalesce(count(d.DiscussionID), 0) from GDN_Discussion d where c.CategoryID = d.CategoryID);

-- Count comments.
update GDN_Discussion d
set CountComments = (select coalesce(count(c.CommentID), 0) from GDN_Comment c where c.DiscussionID = d.DiscussionID);

update GDN_Category c
set CountComments = (select coalesce(sum(d.CountComments), 0) from GDN_Discussion d where c.CategoryID = d.CategoryID);

-- Update date last comment and last post.
update GDN_Discussion d
set DateLastComment = (select coalesce(max(c.DateInserted), d.DateInserted) from GDN_Comment c where c.DiscussionID = d.DiscussionID);

update GDN_Discussion d
join GDN_Comment c
	on c.DiscussionID = d.DiscussionID and d.DateLastComment = c.DateInserted
set LastCommentID = c.CommentID;

update GDN_Category cat
set LastDateInserted = (select max(d.DateLastComment) from GDN_Discussion d where d.CategoryID = cat.CategoryID);

update GDN_Category cat
join GDN_Discussion d
	on d.CategoryID = cat.CategoryID and d.DateLastComment = cat.`LastDateInserted`
set cat.LastCommentID = d.LastCommentID,
	cat.LastDiscussionID = d.DiscussionID;