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Support ANSI SQL2003 window functions.

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1 parent 6e427e5 commit a1a6fbc189d0cb8c44606eafcb8bda7a010554c0 Alexander Staubo committed Feb 22, 2012
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@@ -3,6 +3,7 @@
require 'arel/expressions'
require 'arel/predications'
+require 'arel/window_predications'
require 'arel/math'
require 'arel/alias_predication'
require 'arel/order_predications'
View
@@ -26,6 +26,7 @@
require 'arel/nodes/delete_statement'
require 'arel/nodes/table_alias'
require 'arel/nodes/infix_operation'
+require 'arel/nodes/over'
# nary
require 'arel/nodes/and'
@@ -38,6 +39,9 @@
require 'arel/nodes/values'
require 'arel/nodes/named_function'
+# windows
+require 'arel/nodes/window'
+
# joins
require 'arel/nodes/inner_join'
require 'arel/nodes/outer_join'
@@ -3,6 +3,7 @@ module Nodes
class Function < Arel::Nodes::Node
include Arel::Expression
include Arel::Predications
+ include Arel::WindowPredications
attr_accessor :expressions, :alias, :distinct
def initialize expr, aliaz = nil
View
@@ -0,0 +1,13 @@
+module Arel
+ module Nodes
+
+ class Over < Binary
+ def initialize(left, right = nil)
+ super(left, right)
+ end
+
+ def operator; 'OVER' end
+ end
+
+ end
+end
@@ -1,7 +1,7 @@
module Arel
module Nodes
class SelectCore < Arel::Nodes::Node
- attr_accessor :top, :projections, :wheres, :groups
+ attr_accessor :top, :projections, :wheres, :groups, :windows
attr_accessor :having, :source, :set_quantifier
def initialize
@@ -14,6 +14,7 @@ def initialize
@wheres = []
@groups = []
@having = nil
+ @windows = []
end
def from
@@ -34,6 +35,7 @@ def initialize_copy other
@wheres = @wheres.clone
@groups = @groups.clone
@having = @having.clone if @having
+ @windows = @windows.clone
end
end
end
View
@@ -0,0 +1,78 @@
+module Arel
+ module Nodes
+ class Window < Arel::Nodes::Node
+ include Arel::Expression
+ attr_accessor :orders, :framing
+
+ def initialize
+ @orders = []
+ end
+
+ def order *expr
+ # FIXME: We SHOULD NOT be converting these to SqlLiteral automatically
+ @orders.concat expr.map { |x|
+ String === x || Symbol === x ? Nodes::SqlLiteral.new(x.to_s) : x
+ }
+ self
+ end
+
+ def frame(expr)
+ raise ArgumentError, "Window frame cannot be set more than once" if @frame
+ @framing = expr
+ end
+
+ def rows(expr = nil)
+ frame(Rows.new(expr))
+ end
+
+ def range(expr = nil)
+ frame(Range.new(expr))
+ end
+
+ def initialize_copy other
+ super
+ @orders = @orders.map { |x| x.clone }
+ end
+ end
+
+ class NamedWindow < Window
+ attr_accessor :name
+
+ def initialize name
+ super()
+ @name = name
+ end
+
+ def initialize_copy other
+ super
+ @name = other.name.clone
+ end
+ end
+
+ class Rows < Unary
+ def initialize(expr = nil)
+ super(expr)
+ end
+ end
+
+ class Range < Unary
+ def initialize(expr = nil)
+ super(expr)
+ end
+ end
+
+ class CurrentRow < Arel::Nodes::Node; end
+
+ class Preceding < Unary
+ def initialize(expr = nil)
+ super(expr)
+ end
+ end
+
+ class Following < Unary
+ def initialize(expr = nil)
+ super(expr)
+ end
+ end
+ end
+end
@@ -126,6 +126,12 @@ def having *exprs
self
end
+ def window name
+ window = Nodes::NamedWindow.new(name)
+ @ctx.windows.push window
+ window
+ end
+
def project *projections
# FIXME: converting these to SQLLiterals is probably not good, but
# rails tests require it.
@@ -110,6 +110,7 @@ def terminal o
alias :visit_Arel_Nodes_Node :terminal
alias :visit_Arel_Nodes_SqlLiteral :terminal
alias :visit_Arel_Nodes_BindParam :terminal
+ alias :visit_Arel_Nodes_Window :terminal
alias :visit_Arel_SqlLiteral :terminal
alias :visit_BigDecimal :terminal
alias :visit_Bignum :terminal
@@ -136,6 +137,7 @@ def visit_Arel_Nodes_SelectCore o
visit o.source
visit o.wheres
visit o.groups
+ visit o.windows
visit o.having
end
View
@@ -74,6 +74,23 @@ def unary o
alias :visit_Arel_Nodes_On :unary
alias :visit_Arel_Nodes_Top :unary
alias :visit_Arel_Nodes_UnqualifiedColumn :unary
+ alias :visit_Arel_Nodes_Preceding :unary
+ alias :visit_Arel_Nodes_Following :unary
+ alias :visit_Arel_Nodes_Rows :unary
+ alias :visit_Arel_Nodes_Range :unary
+
+ def window o
+ visit_edge o, "orders"
+ visit_edge o, "framing"
+ end
+ alias :visit_Arel_Nodes_Window :window
+
+ def named_window o
+ visit_edge o, "orders"
+ visit_edge o, "framing"
+ visit_edge o, "name"
+ end
+ alias :visit_Arel_Nodes_NamedWindow :named_window
def function o
visit_edge o, "expressions"
@@ -103,6 +120,7 @@ def visit_Arel_Nodes_SelectCore o
visit_edge o, "source"
visit_edge o, "projections"
visit_edge o, "wheres"
+ visit_edge o, "windows"
end
def visit_Arel_Nodes_SelectStatement o
@@ -159,6 +177,7 @@ def binary o
alias :visit_Arel_Nodes_NotEqual :binary
alias :visit_Arel_Nodes_NotIn :binary
alias :visit_Arel_Nodes_Or :binary
+ alias :visit_Arel_Nodes_Over :binary
def visit_String o
@node_stack.last.fields << o
@@ -136,6 +136,7 @@ def visit_Arel_Nodes_SelectCore o
("WHERE #{o.wheres.map { |x| visit x }.join ' AND ' }" unless o.wheres.empty?),
("GROUP BY #{o.groups.map { |x| visit x }.join ', ' }" unless o.groups.empty?),
(visit(o.having) if o.having),
+ ("WINDOW #{o.windows.map { |x| visit x }.join ', ' }" unless o.windows.empty?)
].compact.join ' '
end
@@ -175,6 +176,59 @@ def visit_Arel_Nodes_Except o
"( #{visit o.left} EXCEPT #{visit o.right} )"
end
+ def visit_Arel_Nodes_NamedWindow o
+ "#{quote_column_name o.name} AS #{visit_Arel_Nodes_Window o}"
+ end
+
+ def visit_Arel_Nodes_Window o
+ s = [
+ ("ORDER BY #{o.orders.map { |x| visit(x) }.join(', ')}" unless o.orders.empty?),
+ (visit o.framing if o.framing)
+ ].compact.join ' '
+ "(#{s})"
+ end
+
+ def visit_Arel_Nodes_Rows o
+ if o.expr
+ "ROWS #{visit o.expr}"
+ else
+ "ROWS"
+ end
+ end
+
+ def visit_Arel_Nodes_Range o
+ if o.expr
+ "RANGE #{visit o.expr}"
+ else
+ "RANGE"
+ end
+ end
+
+ def visit_Arel_Nodes_Preceding o
+ "#{o.expr ? visit(o.expr) : 'UNBOUNDED'} PRECEDING"
+ end
+
+ def visit_Arel_Nodes_Following o
+ "#{o.expr ? visit(o.expr) : 'UNBOUNDED'} FOLLOWING"
+ end
+
+ def visit_Arel_Nodes_CurrentRow o
+ "CURRENT ROW"
+ end
+
+ def visit_Arel_Nodes_Over o
+ case o.right
+ when nil
+ "#{visit o.left} OVER ()"
+ when Arel::Nodes::SqlLiteral
+ "#{visit o.left} OVER #{visit o.right}"
+ when String, Symbol
+ "#{visit o.left} OVER #{quote_column_name o.right.to_s}"
+ else
+ "#{visit o.left} OVER #{visit o.right}"
+ end
+ end
+
def visit_Arel_Nodes_Having o
"HAVING #{visit o.expr}"
end
@@ -0,0 +1,9 @@
+module Arel
+ module WindowPredications
+
+ def over(expr = nil)
+ Nodes::Over.new(self, expr)
+ end
+
+ end
+end
View
@@ -0,0 +1,40 @@
+require 'helper'
+
+describe Arel::Nodes::Over do
+ describe 'with literal' do
+ it 'should reference the window definition by name' do
+ table = Arel::Table.new :users
+ table[:id].count.over('foo').to_sql.must_be_like %{
+ COUNT("users"."id") OVER "foo"
+ }
+ end
+ end
+
+ describe 'with SQL literal' do
+ it 'should reference the window definition by name' do
+ table = Arel::Table.new :users
+ table[:id].count.over(Arel.sql('foo')).to_sql.must_be_like %{
+ COUNT("users"."id") OVER foo
+ }
+ end
+ end
+
+ describe 'with no expression' do
+ it 'should use empty definition' do
+ table = Arel::Table.new :users
+ table[:id].count.over.to_sql.must_be_like %{
+ COUNT("users"."id") OVER ()
+ }
+ end
+ end
+
+ describe 'with expression' do
+ it 'should use definition in sub-expression' do
+ table = Arel::Table.new :users
+ window = Arel::Nodes::Window.new.order(table['foo'])
+ table[:id].count.over(window).to_sql.must_be_like %{
+ COUNT("users"."id") OVER (ORDER BY \"users\".\"foo\")
+ }
+ end
+ end
+end
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