Plucking multiple columns from a rails 3 app could be a pain in the ass. Fortunately rails 4 addressed this but still for those still running on the previous versions of rails this is still an issue.
A few days ago, i was trying to see how many people have logged in into my application and wanted to display their sign_in_count next to their email addresses. Usually this is simple in rails 4 as you can just do
User.where('sign_in_count > 0').pluck(:email, :sign_in_count)
The app is runs on rails 3 and the pluck method in Rails 3 only allows plucking a single column, so we had to find a way to make our owm method to overcome this.
Thanks to monkey-patching, we just had to re-open the Active Record Module and add the mothod, check the code below, put that code in the config/initializers directory, restart your application and you’re good to go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
module ActiveRecord
class Relation
def pluck_multiple(*args)
args.map! do |column_name|
if column_name.is_a?(Symbol) &&
column_names.include?(column_name.to_s)
"#{connection.quote_table_name(table_name)}.#{connection.quote_column_name(column_name)}"
else
column_name.to_s
end
end
relation = clone
relation.select_values = args
klass.connection.select_all(relation.arel).map! do |attributes|
initialized_attributes = klass.initialize_attributes(attributes)
attributes.each do |key, attribute|
attributes[key] = klass.type_cast_attribute(key, initialized_attributes)
end
end
end
end
end
Now you can just do
User.where('sign_in_count > 0').pluck_multiple(:email, :sign_in_count)
Remember, my User Model is a devise model