MySQL errors in Dashboard

[JW]

In Admin::DashboardController is written:
    @most_active_commenter = Comment.find(:first, {:select => "author, website",
      :order => "COUNT(author) DESC", :conditions => "approved = 1"})
this executes the SQL:
    SELECT author, website FROM comments WHERE (approved = 1) ORDER BY COUNT(author) DESC LIMIT 1
which returns the error:
    Invalid use of group function
This happens because we're using an aggregate function (COUNT) in the ORDER BY clause.
More info about this message is, amongst others, at http://sqlzoo.net/howto/source/z.dir/err934/mysql and http://www.thescripts.com/forum/thread691615.html.

An example of this bug is on http://chameleon.wikidot.com/forum/t-28692/production-problems-with-dashboard-and-comments#post-74110, the first one.

[JW (jw-00000)]

A possible solution is the query
    SELECT author, website, COUNT(author) FROM comments WHERE approved = 1
    GROUP BY author ORDER BY COUNT(author) DESC LIMIT 1

[JW (jw-00000)]

The first solution doesn't work, this will:
    SELECT author, website, COUNT(author) as count FROM comments
    WHERE approved = 1 GROUP BY author ORDER BY count DESC LIMIT 1
This is the same as the first, only now we're naming COUNT(author) 'count',

[JW (jw-00000)]

This same problem happens with the code:
    @most_used_tags = Tag.find_by_sql "SELECT name, COUNT(*) AS count " +
      "FROM tags JOIN entries_tags ON tags.id = entries_tags.tag_id " +
      "GROUP BY name ORDER BY count DESC LIMIT 5"
in Admin::DashboardController#welcome.
Changing the SQL to this should work:
    SELECT name, COUNT(*) AS count FROM tags JOIN entries_tags ON tags.id = entries_tags.tag_id
    GROUP BY name ORDER BY count DESC LIMIT 5

[JW (jw-00000)]

Fixed in trunk.