Class: Sequel::SQL::Window

Inherits:
Expression show all
Defined in:
lib/sequel/sql.rb

Overview

A Window is part of a window function specifying the window over which a window function operates.

Sequel::SQL::Window.new(partition: :col1)
# (PARTITION BY col1)
Sequel::SQL::Window.new(partition: [:col2, :col3])
# (PARTITION BY col2, col3)

Sequel::SQL::Window.new(order: :col4)
# (ORDER BY col4)
Sequel::SQL::Window.new(order: [:col5, Sequel.desc(:col6)])
# (ORDER BY col5, col6 DESC)

Sequel::SQL::Window.new(partition: :col7, frame: :all)
# (PARTITION BY col7 ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING)
Sequel::SQL::Window.new(partition: :col7, frame: :rows)
# (PARTITION BY col7 ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW)
Sequel::SQL::Window.new(partition: :col7, frame: {type: :range, start: current})
# (PARTITION BY col7 RANGE CURRENT ROW)
Sequel::SQL::Window.new(partition: :col7, frame: {type: :range, start: 1, end: 1})
# (PARTITION BY col7 RANGE BETWEEN 1 PRECEDING AND 1 FOLLOWING)
Sequel::SQL::Window.new(partition: :col7, frame: {type: :range, start: 2, end: [1, :preceding]})
# (PARTITION BY col7 RANGE BETWEEN 2 PRECEDING AND 1 PRECEDING)
Sequel::SQL::Window.new(partition: :col7, frame: {type: :range, start: 1, end: [2, :following]})
# (PARTITION BY col7 RANGE BETWEEN 1 FOLLOWING AND 2 FOLLOWING)
Sequel::SQL::Window.new(partition: :col7, frame: {type: :range, start: :preceding, exclude: :current})
# (PARTITION BY col7 RANGE UNBOUNDED PRECEDING EXCLUDE CURRENT ROW)

Sequel::SQL::Window.new(window: :named_window) # you can create a named window with Dataset#window
# (named_window)

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from Expression

#==, attr_reader, #clone, #eql?, #hash, inherited, #inspect

Constructor Details

#initialize(opts = OPTS) ⇒ Window

Set the options to the options given



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# File 'lib/sequel/sql.rb', line 1995

def initialize(opts=OPTS)
  @opts = opts.frozen? ? opts : Hash[opts].freeze
  freeze
end

Instance Attribute Details

#opts ⇒ Object (readonly)

The options for this window. Options currently supported: :frame :: if specified, should be :all, :rows, :range, :groups, a String, or a Hash. :all :: Always operates over all rows in the partition :rows :: Includes rows in the partition up to and including the current row :range, :groups :: Includes rows in the partition up to and including the current group

      String :: Used as literal SQL code, try to avoid
      Hash :: Hash of options for the frame:
              :type :: The type of frame, must be :rows, :range, or :groups (required)
              :start :: The start of the frame (required).  Possible values:
                        :preceding :: UNBOUNDED PRECEDING
                        :following :: UNBOUNDED FOLLOWING
                        :current :: CURRENT ROW
                        String, Numeric, or Cast :: Used as the offset of rows/values preceding
                        Array :: Must have two elements, with first element being String, Numeric, or
                                 Cast and second element being :preceding or :following
              :end :: The end of the frame.  Can be left out.  If present, takes the same values as
                      :start, except that when a String, Numeric, or Hash, it is used as the offset
                      for rows following
              :exclude :: Which rows to exclude.  Possible values are :current, :ties, :group
                          :no_others.

:order :: order on the column(s) given :partition :: partition/group on the column(s) given :window :: base results on a previously specified named window



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# File 'lib/sequel/sql.rb', line 1992

def opts
  @opts
end