DataMapper plugin providing support for aggregates, functions on collections and datasets.
It provides the following functions:
== count
Count results (given the conditions)
Friend.count # returns count of all friends Friend.count(:age.gt => 18) # returns count of all friends older then 18 Friend.count(:conditions => [ 'gender = ?', 'female' ]) # returns count of all your female friends Friend.count(:address) # returns count of all friends with an address (NULL values are not included) Friend.count(:address, :age.gt => 18) # returns count of all friends with an address that are older then 18 Friend.count(:address, :conditions => [ 'gender = ?', 'female' ]) # returns count of all your female friends with an address
== min
Get the lowest value of a property
Friend.min(:age) # returns the age of the youngest friend Friend.min(:age, :conditions => [ 'gender = ?', 'female' ]) # returns the age of the youngest female friends
== max
Get the highest value of a property
Friend.max(:age) # returns the age of the oldest friend Friend.max(:age, :conditions => [ 'gender = ?', 'female' ]) # returns the age of the oldest female friends
== avg
Get the average value of a property
Friend.avg(:age) # returns the average age of friends Friend.avg(:age, :conditions => [ 'gender = ?', 'female' ]) # returns the average age of the female friends
== sum
Get the total value of a property
Friend.sum(:age) # returns total age of all friends Friend.sum(:age, :conditions => [ 'gender = ?', 'female' ]) # returns the total age of all female friends