arel_table_example.rb

Task.select(
  Arel::Nodes::NamedFunction.new(
    'to_char', 
    [
      Task.arel_table[:created_at], 
      Arel::Nodes.build_quoted('YYYY')
    ]
  ).as('year')
)
# => SELECT to_char("tasks"."created_at", 'YYYY') AS year FROM "tasks"

Task.where(
  Arel::Nodes::InfixOperation.new(
    '->', 
    Task.arel_table['attr_values'], 
    Arel::Nodes.build_quoted('foo')
  ).eq(
    'bar'
  )
)
# => SELECT "tasks".* FROM "tasks" WHERE "tasks"."attr_values" -> 'foo' = 'bar'

Task.order(Arel::Nodes::InfixOperation.new('=', Task.arel_table['id'], 123).desc)
# => SELECT `tasks`.* FROM `companies` ORDER BY `tasks`.`id` = 123 DESC