Class: Sequel::SQL::Window

Inherits:

Expression

• Object
• Expression
• Sequel::SQL::Window

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

• #opts ⇒ Object readonly

  The options for this window.

Instance Method Summary

• #initialize(opts = OPTS) ⇒ Window constructor

  Set the options to the options given.

Methods inherited from Expression

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

Constructor Details

#initialize(opts = OPTS) ⇒ Window

Set the options to the options given

# 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

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

def opts
  @opts
end