method
sum
v2.3.8 -
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- Class:
ActiveRecord::Calculations::ClassMethods
sum(column_name, options = {})public
Calculates the sum of values on a given column. The value is returned with the same data type of the column, 0 if there’s no row. See calculate for examples with options.
Person.sum('age') # => 4562
2Notes
Expressions in the sum method
=== Person.sum("2 * age") Person.sum(:age, :conditions=>'1 = 2')
Grouping
====
Person.sum(:age, :group => "sex") # =>[["male",2500],["female",2200]]
