Ruby on rails Rails 3活动记录计算:同时求和和和平均值
有没有办法让activerecord同时计算Ruby on rails Rails 3活动记录计算:同时求和和和平均值,ruby-on-rails,activerecord,Ruby On Rails,Activerecord,有没有办法让activerecord同时计算查询的总和和平均值 例如,我想做一些像这样的事情-这是行不通的 Person.group("gender").count.average("age") 回来 Gender Count Average Age Male 32 13.5 Female 26 14.7 不太漂亮,但还是不太漂亮 Person.select('gender, count(*) as count, avg(age) as avg').
查询
的总和和平均值
例如,我想做一些像这样的事情-这是行不通的
Person.group("gender").count.average("age")
回来
Gender Count Average Age
Male 32 13.5
Female 26 14.7
不太漂亮,但还是不太漂亮
Person.select('gender, count(*) as count, avg(age) as avg').
group('gender').
order('count DESC').
each do |p|
puts "#{p.gender} #{p.count} #{p.avg}"
end