Absolute value in AREL (rails)

Question

Absolute value in AREL (rails)

I need to do some absolute values in AREL. Basically you need to understand how to execute this line (in relational algebra) with ARel:

Suppose P is a table with columns value1 and value2:

Project((|p.value1 - 10| + |p.value2 - 10|) as match) P

Not sure if this is possible with AREL.

Thanks in advance!

+3

ruby-on-rails arel relational-algebra

Nima gardideh 13 Mar 12 at 19:12

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1 answer

Winfield · Accepted Answer · 2012-04-19T18:39:06+0000

You'd better do this SQL:

class Project < ActiveRecord::Base
  def self.abs_values
    connection.select_values('SELECT abs(value1-10), abs(value2-10) FROM projects')
  end
end

Absolute value in AREL (rails)

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