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 collapse
-
#opts ⇒ Object
readonly
The options for this window.
Instance Method Summary collapse
-
#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
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
1989 1990 1991 |
# File 'lib/sequel/sql.rb', line 1989 def opts @opts end |