ruby on rails - query , can not select column count

Question

Tag.joins(:quote_tags).group('quote_tags.tag_id').order('count desc').select('count(tags.id) AS count, tags.id, tags.name')

Build query:
SELECT count(tags.id) AS count, tags.id, tags.name FROM `tags` INNER JOIN `quote_tags` ON `quote_tags`.`tag_id` = `tags`.`id` GROUP BY quote_tags.tag_id ORDER BY count desc

Result:

[#<Tag id: 401, name: "different">, ... , #<Tag id: 4, name: "family">]

It not return count column for me. How can I get it?

Answer 1

Have you tried calling the count method on one of the returned Tag objects? Just because inspect doesn't mention the count doesn't mean that it isn't there. The inspect output:

[#<Tag id: 401, name: "different">, ... , #<Tag id: 4, name: "family">]

will only include things that the Tag class knows about and Tag will only know about the columns in the tags table: you only have id and name in the table so that's all you see.

If you do this:

tags = Tag.joins(:quote_tags).group('quote_tags.tag_id').order('count desc').select('count(tags.id) AS count, tags.id, tags.name')

and then look at the counts:

tags.map(&:count)

You'll see the array of counts that you're expecting.