class Sequel::SQL::OrderedExpression

Represents a column/expression to order the result set by.

Constants

INVERT_NULLS

Attributes

descending[R]

Whether the expression should order the result set in a descending manner

expression[R]

The expression to order the result set by.

nulls[R]

Whether to sort NULLS FIRST/LAST

Public Class Methods

new(expression, descending = true, opts=OPTS) click to toggle source

Set the expression and descending attributes to the given values. Options:

:nulls: Can be :first/:last for NULLS FIRST/LAST.

     # File lib/sequel/sql.rb
1683 def initialize(expression, descending = true, opts=OPTS)
1684   @expression = expression
1685   @descending = descending
1686   @nulls = opts[:nulls]
1687   freeze
1688 end

Public Instance Methods

asc() click to toggle source

Return a copy that is ordered ASC

     # File lib/sequel/sql.rb
1691 def asc
1692   OrderedExpression.new(@expression, false, :nulls=>@nulls)
1693 end

desc() click to toggle source

Return a copy that is ordered DESC

     # File lib/sequel/sql.rb
1696 def desc
1697   OrderedExpression.new(@expression, true, :nulls=>@nulls)
1698 end

invert() click to toggle source

Return an inverted expression, changing ASC to DESC and NULLS FIRST to NULLS LAST.

     # File lib/sequel/sql.rb
1701 def invert
1702   OrderedExpression.new(@expression, !@descending, :nulls=>INVERT_NULLS.fetch(@nulls, @nulls))
1703 end

Private Instance Methods

inspect_args() click to toggle source

OrderedExpression’s initializer takes the :nulls information inside a hash, so if a NULL order was given, include a hash with that information.

    # File lib/sequel/extensions/eval_inspect.rb
171 def inspect_args
172   if nulls
173     [:expression, :descending, :opts_hash]
174   else
175     [:expression, :descending]
176   end
177 end

opts_hash() click to toggle source

A hash of null information suitable for passing to the initializer.

    # File lib/sequel/extensions/eval_inspect.rb
180 def opts_hash
181   {:nulls=>nulls} 
182 end