diff options
Diffstat (limited to 'activerecord/lib/active_record/relation/calculations.rb')
-rw-r--r-- | activerecord/lib/active_record/relation/calculations.rb | 33 |
1 files changed, 32 insertions, 1 deletions
diff --git a/activerecord/lib/active_record/relation/calculations.rb b/activerecord/lib/active_record/relation/calculations.rb index af86771d2d..63365e501b 100644 --- a/activerecord/lib/active_record/relation/calculations.rb +++ b/activerecord/lib/active_record/relation/calculations.rb @@ -166,6 +166,37 @@ module ActiveRecord 0 end + # This method is designed to perform select by a single column as direct SQL query + # Returns <tt>Array</tt> with values of the specified column name + # The values has same data type as column. + # + # Examples: + # + # Person.pluck(:id) # SELECT people.id FROM people + # Person.uniq.pluck(:role) # SELECT DISTINCT role FROM people + # Person.where(:confirmed => true).limit(5).pluck(:id) + # + def pluck(column_name) + key = column_name.to_s.split('.', 2).last + + if column_name.is_a?(Symbol) && column_names.include?(column_name.to_s) + column_name = "#{table_name}.#{column_name}" + end + + result = klass.connection.select_all(select(column_name).arel) + types = result.column_types.merge klass.column_types + column = types[key] + + result.map do |attributes| + value = klass.initialize_attributes(attributes)[key] + if column + column.type_cast value + else + value + end + end + end + private def perform_calculation(operation, column_name, options = {}) @@ -317,7 +348,7 @@ module ActiveRecord def select_for_count if @select_values.present? select = @select_values.join(", ") - select if select !~ /(,|\*)/ + select if select !~ /[,*]/ end end |