[ActiveRecord] feature request - QueryMethods method that augments the select clause.

rubyonrails-core
1

One little pet peeve of mine is that there is no way (afaik) to just add additional columns to the select clause of a query. Like for example if I’m joining and want a count or aggregate off the join table:

User.joins(:answers) .select(‘users.*’,‘AVG(answers.score) AS average_score’)

``

What I would really want to do is just add this to the existing select values of the scope:

User.joins(:answers) .select_also(‘AVG(answers.score) AS average_score’)

``

**Is this a worthwhile feature? **

2

I’ve had this too. I think I delegated it to select_with? Same behavior different name. I’m wondering what the most Rails-y name would be.

3

+1

4

I like it, but I don’t think it meets the criteria for inclusion in rails because it:

  • Could easily be a gem.

  • Is not meaningfully shorter.

    * Requires the next person to read this code to know what this

method does.

5

Its not so much that’s it’s shorter. They produce very different queries. Rails by default selects all the columns explicitly instead of using *.

If eager_load is used this becomes even more of a hassle since you also have to worry about selecting the the rows on the other table.

I really feel that there should be a built in method that matches the behavior of .where which does not clobber.

6

Sorry, I was being unclear there.

I think it might be sensible to convert .select(“users.*, sum(baz))” to the expanded form on the ruby side using the column cache. That way you get the functionality you want without introducing a new API.

Thanks, Daniel Heath