ActiveRecord::Calculations#pluck accepts multiple columns

[jeroeningen]

Rails currently supports this:
Person.pluck(:id) # SELECT people.id FROM people

I added two possibilities:
Person.pluck(:id) # SELECT people.id FROM people
Person.pluck([:id, :name]) # SELECT people.id, people.name FROM people
Person.pluck(:id, :name) # SELECT people.id, people.name FROM people

Because I made some stupid mistakes while updating my own fork of rails/rails this is a new fork and a follow up of the discussion located here: #5472

[steveklabnik]

Mentioning #5472 so that GitHub links them.

[carlosantoniodasilva]

Columns need to be typecasted in both scenarios, otherwise pluck would work differently when using 1 and more columns.

[jonleighton]

I think we should probably have this feature as people keep asking about it. However I think we should decide between Post.pluck([:a, :b]) and Post.pluck(:a, :b) and just support one of them. I think probably the latter.

[jeroeningen]

@carlos, you were right with your comment my mistakes. Just fixed and pushed it!

@jon In my previous pull request, several people liked it (see #5472). So IMO that's not the problem. But why do you want to support just one of the possibilities of Post.pluck([:a, :b]) and Post.pluck(:a, :b) and not both?

[carlosantoniodasilva]

@jeroeningen I've pulled your changes and modified as per @jonleighton comments: d59b2ab. Thanks for your work on that :).

[RKushnir]

How about if pluck would also account for the select arguments? So Model.select([:id, :name]).pluck would project id and name.

[carlosantoniodasilva]

@RKushnir we've just merged a change that will ignore the select values in 3a33572. If you think it can be improved, please feel free to open a new topic in the core mailing list. Thanks.