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-rw-r--r--activerecord/lib/active_record/relation/calculations.rb17
1 files changed, 17 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/relation/calculations.rb b/activerecord/lib/active_record/relation/calculations.rb
index af86771d2d..0f57e9831d 100644
--- a/activerecord/lib/active_record/relation/calculations.rb
+++ b/activerecord/lib/active_record/relation/calculations.rb
@@ -166,6 +166,23 @@ 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)
+ scope = self.select(column_name)
+ self.connection.select_values(scope.to_sql).map! do |value|
+ type_cast_using_column(value, column_for(column_name))
+ end
+ end
+
private
def perform_calculation(operation, column_name, options = {})