module Sequel::MSSQL::EmulateLateralWithApply
Public Instance Methods
from(*source, &block)
click to toggle source
When a FROM entry uses a LATERAL subquery, convert that entry into a CROSS APPLY.
Calls superclass method
# File lib/sequel/extensions/mssql_emulate_lateral_with_apply.rb, line 58 def from(*source, &block) virtual_row_columns(source, block) lateral, source = source.partition{|t| t.is_a?(Sequel::Dataset) && t.opts[:lateral] || (t.is_a?(Sequel::SQL::AliasedExpression) && t.expression.is_a?(Sequel::Dataset) && t.expression.opts[:lateral])} unless source.empty? return super(*source, &nil) if !lateral || lateral.empty? ds = from(*source) lateral.each do |l| l = if l.is_a?(Sequel::SQL::AliasedExpression) l.expression.clone(:lateral=>nil).as(l.alias) else l.clone(:lateral=>nil) end ds = ds.cross_apply(l) end ds end
join_table(type, table, expr=nil, *)
click to toggle source
If the table is a dataset that uses LATERAL, convert it to a CROSS APPLY if it is a INNER or CROSS JOIN, and an OUTER APPLY if it is a LEFT JOIN.
Calls superclass method
# File lib/sequel/extensions/mssql_emulate_lateral_with_apply.rb, line 37 def join_table(type, table, expr=nil, *) if table.is_a?(Dataset) && table.opts[:lateral] table = table.clone(:lateral=>nil) case type when :inner type = :cross_apply table = table.where(expr) expr = nil when :cross type = :cross_apply when :left, :left_outer type = :outer_apply table = table.where(expr) expr = nil end end super end
supports_lateral_subqueries?()
click to toggle source
MSSQL can emulate lateral subqueries via CROSS/OUTER APPLY when using this extension.
# File lib/sequel/extensions/mssql_emulate_lateral_with_apply.rb, line 77 def supports_lateral_subqueries? true end