diff options
Diffstat (limited to 'activerecord/lib/active_record/calculations.rb')
| -rw-r--r-- | activerecord/lib/active_record/calculations.rb | 54 |
1 files changed, 1 insertions, 53 deletions
diff --git a/activerecord/lib/active_record/calculations.rb b/activerecord/lib/active_record/calculations.rb index 41acf7be4e..ea63617c52 100644 --- a/activerecord/lib/active_record/calculations.rb +++ b/activerecord/lib/active_record/calculations.rb @@ -3,59 +3,7 @@ module ActiveRecord extend ActiveSupport::Concern module ClassMethods - delegate :count, :average, :minimum, :maximum, :sum, :to => :scoped - - # This calculates aggregate values in the given column. Methods for count, sum, average, minimum, and maximum have been added as shortcuts. - # Options such as <tt>:conditions</tt>, <tt>:order</tt>, <tt>:group</tt>, <tt>:having</tt>, and <tt>:joins</tt> can be passed to customize the query. - # - # There are two basic forms of output: - # * Single aggregate value: The single value is type cast to Fixnum for COUNT, Float for AVG, and the given column's type for everything else. - # * Grouped values: This returns an ordered hash of the values and groups them by the <tt>:group</tt> option. It takes either a column name, or the name - # of a belongs_to association. - # - # values = Person.maximum(:age, :group => 'last_name') - # puts values["Drake"] - # => 43 - # - # drake = Family.find_by_last_name('Drake') - # values = Person.maximum(:age, :group => :family) # Person belongs_to :family - # puts values[drake] - # => 43 - # - # values.each do |family, max_age| - # ... - # end - # - # Options: - # * <tt>:conditions</tt> - An SQL fragment like "administrator = 1" or [ "user_name = ?", username ]. See conditions in the intro to ActiveRecord::Base. - # * <tt>:include</tt>: Eager loading, see Associations for details. Since calculations don't load anything, the purpose of this is to access fields on joined tables in your conditions, order, or group clauses. - # * <tt>:joins</tt> - An SQL fragment for additional joins like "LEFT JOIN comments ON comments.post_id = id". (Rarely needed). - # The records will be returned read-only since they will have attributes that do not correspond to the table's columns. - # * <tt>:order</tt> - An SQL fragment like "created_at DESC, name" (really only used with GROUP BY calculations). - # * <tt>:group</tt> - An attribute name by which the result should be grouped. Uses the GROUP BY SQL-clause. - # * <tt>:select</tt> - By default, this is * as in SELECT * FROM, but can be changed if you for example want to do a join, but not - # include the joined columns. - # * <tt>:distinct</tt> - Set this to true to make this a distinct calculation, such as SELECT COUNT(DISTINCT posts.id) ... - # - # Examples: - # Person.calculate(:count, :all) # The same as Person.count - # Person.average(:age) # SELECT AVG(age) FROM people... - # Person.minimum(:age, :conditions => ['last_name != ?', 'Drake']) # Selects the minimum age for everyone with a last name other than 'Drake' - # Person.minimum(:age, :having => 'min(age) > 17', :group => :last_name) # Selects the minimum age for any family without any minors - # Person.sum("2 * age") - def calculate(operation, column_name, options = {}) - construct_calculation_arel(options).calculate(operation, column_name, options.slice(:distinct)) - rescue ThrowResult - 0 - end - - private - - def construct_calculation_arel(options = {}) - relation = scoped.apply_finder_options(options.except(:distinct)) - (relation.eager_loading? || relation.includes_values.present?) ? relation.send(:construct_relation_for_association_calculations) : relation - end - + delegate :count, :average, :minimum, :maximum, :sum, :calculate, :to => :scoped end end end |