diff options
Diffstat (limited to 'activerecord/lib/active_record')
-rw-r--r-- | activerecord/lib/active_record/calculations.rb | 58 |
1 files changed, 27 insertions, 31 deletions
diff --git a/activerecord/lib/active_record/calculations.rb b/activerecord/lib/active_record/calculations.rb index daed53d60c..74fdec363f 100644 --- a/activerecord/lib/active_record/calculations.rb +++ b/activerecord/lib/active_record/calculations.rb @@ -115,19 +115,21 @@ module ActiveRecord # 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 def calculate(operation, column_name, options = {}) - column_name = '*' if column_name == :all - column = columns.detect { |c| c.name.to_s == column_name.to_s } + column_name = '*' if column_name == :all + column = columns.detect { |c| c.name.to_s == column_name.to_s } + aggregate = select_aggregate(operation, column_name, options) + aggregate_alias = column_alias_for(operation, column_name) if options[:group] - execute_grouped_calculation(operation, column_name, column, options) + execute_grouped_calculation(operation, column_name, column, aggregate, aggregate_alias, options) else - execute_simple_calculation(operation, column_name, column, options) + execute_simple_calculation(operation, column_name, column, aggregate, aggregate_alias, options) end end protected - def construct_calculation_sql(operation, column_name, options) - sql = ["SELECT #{operation}(#{'DISTINCT ' if options[:distinct]}#{column_name})"] - sql << ", #{options[:group_field]}" if options[:group] + def construct_calculation_sql(aggregate, aggregate_alias, options) + sql = ["SELECT #{aggregate} AS #{aggregate_alias}"] + sql << ", #{options[:group_field]} AS #{options[:group_alias]}" if options[:group] sql << " FROM #{table_name} " add_joins!(sql, options) add_conditions!(sql, options[:conditions]) @@ -136,52 +138,46 @@ module ActiveRecord sql.join end - def execute_simple_calculation(operation, column_name, column, options) - value = connection.select_value(construct_calculation_sql(operation, column_name, options)) + def execute_simple_calculation(operation, column_name, column, aggregate, aggregate_alias, options) + value = connection.select_value(construct_calculation_sql(aggregate, aggregate_alias, options)) type_cast_calculated_value(value, column, operation) end - def execute_grouped_calculation(operation, column_name, column, options) + def execute_grouped_calculation(operation, column_name, column, aggregate, aggregate_alias, options) group_attr = options[:group].to_s association = reflect_on_association(group_attr.to_sym) associated = association && association.macro == :belongs_to # only count belongs_to associations group_field = (associated ? "#{options[:group]}_id" : options[:group]).to_s - sql = construct_calculation_sql(operation, column_name, options.merge(:group_field => group_field)) + group_alias = column_alias_for(group_field) + sql = construct_calculation_sql(aggregate, aggregate_alias, options.merge(:group_field => group_field, :group_alias => group_alias)) calculated_data = connection.select_all(sql) if association - key_ids = calculated_data.collect { |row| row[group_field] } + key_ids = calculated_data.collect { |row| row[group_alias] } key_records = ActiveRecord::Base.send(:class_of_active_record_descendant, association.klass).find(key_ids) key_records = key_records.inject({}) { |hsh, r| hsh.merge(r.id => r) } end calculated_data.inject(OrderedHash.new) do |all, row| - key = associated ? key_records[row[group_field].to_i] : row[column_key(group_field)] - value = row[column_key("#{operation}(#{column_name})")] + key = associated ? key_records[row[group_alias].to_i] : row[group_alias] + value = row[aggregate_alias] all << [key, type_cast_calculated_value(value, column, operation)] end end private + def select_aggregate(operation, column_name, options) + "#{operation}(#{'DISTINCT ' if options[:distinct]}#{column_name})" + end + # converts a given key to the value that the database adapter returns as # - # users.id #=> id - # sum(id) #=> sum(id) - # - # psql strips off the () function too - # - # sum(id) #=> sum - # - # Should this go in a DB Adapter? - def column_key(key) - return key.split('.').last unless key =~ /\(/ # split off table alias - case connection - when ActiveRecord::ConnectionAdapters::PostgreSQLAdapter - key.split('(').first.split('.').last - else - sql_func, sql_args = key.split('(') - "#{sql_func.split('.').last}(#{sql_args}" - end + # users.id #=> users_id + # sum(id) #=> sum_id + # count(distinct users.id) #=> count_distinct_users_id + # count(*) #=> count_all + def column_alias_for(*keys) + keys.join(' ').downcase.gsub(/\*/, 'all').gsub(/\W+/, ' ').strip.gsub(/ +/, '_') end def type_cast_calculated_value(value, column, operation) |