Flowdock
method

sum

Importance_3
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. See #calculate for examples with options.

  Person.sum('age')
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September 25, 2008
6 thanks

Expressions in the sum method

Person.sum(“2 * age”)

Person.sum(:age, :conditions=>'1 = 2')
January 18, 2011
2 thanks

Grouping

Person.sum(:age, :group => “sex”) # =>[[“male”,2500],[“female”,2200]]