Merge 38799bc into 5ca6a8d

Gemfile

@@ -3,7 +3,8 @@ source 'https://rubygems.org'
 # Specify your gem's dependencies in activerecord-hierarchical_query.gemspec
 gemspec
 
-gem 'pg', '~> 0.17.1'
+gem 'pg', '~> 0.18.3'
+gem 'activerecord', '~> 4.2.0'
 
 group :local do
   gem 'yard'
@@ -14,4 +15,4 @@ end
 
 group :travis do
   gem 'coveralls'
-end
+end

lib/active_record/hierarchical_query.rb

@@ -50,4 +50,4 @@ class << base
   end
 
   ActiveRecord::Relation.send :include, ActiveRecord::HierarchicalQuery
-end
+end

lib/active_record/hierarchical_query/cte/query_builder.rb

@@ -11,15 +11,17 @@ module CTE
       class QueryBuilder
         attr_reader :query,
                     :columns,
-                    :cycle_detector
+                    :cycle_detector,
+                    :options
 
         delegate :klass, :table, :recursive_table, to: :query
 
         # @param [ActiveRecord::HierarchicalQuery::Query] query
-        def initialize(query)
+        def initialize(query, options: {})
           @query = query
           @columns = Columns.new(@query)
           @cycle_detector = CycleDetector.new(@query)
+          @options = options
         end
 
         def bind_values

lib/active_record/hierarchical_query/cte/recursive_term.rb

@@ -44,4 +44,4 @@ def ordering
       end
     end
   end
-end
+end

lib/active_record/hierarchical_query/cte/union_term.rb

@@ -15,10 +15,17 @@ def bind_values
         end
 
         def arel
-          non_recursive_term.arel.union(:all, recursive_term.arel)
+          non_recursive_term.arel.union(union_type, recursive_term.arel)
         end
 
         private
+
+        def union_type
+          return @builder.options[:union_type] if @builder.options[:union_type].present?
+
+          :all
+        end
+
         def recursive_term
           @rt ||= RecursiveTerm.new(@builder)
         end
@@ -29,4 +36,4 @@ def non_recursive_term
       end
     end
   end
-end
+end

lib/active_record/hierarchical_query/join_builder.rb

@@ -8,7 +8,7 @@ class JoinBuilder
       # @param [#to_s] subquery_alias
       def initialize(query, join_to, subquery_alias, options = {})
         @query = query
-        @builder = CTE::QueryBuilder.new(query)
+        @builder = CTE::QueryBuilder.new(query, options: options)
         @relation = join_to
         @alias = Arel::Table.new(subquery_alias, ActiveRecord::Base)
         @options = options

lib/active_record/hierarchical_query/query.rb

@@ -99,10 +99,10 @@ def start_with(scope = nil, *arguments, &block)
           object = @start_with_value || @klass
 
           @start_with_value = if block.arity == 0
-                                object.instance_eval(&block)
-                              else
-                                block.call(object)
-                              end
+            object.instance_eval(&block)
+          else
+            block.call(object)
+          end
         end
 
         self

lib/arel/nodes/postgresql.rb

@@ -13,6 +13,9 @@ def initialize(values)
 
     class ArrayConcat < Binary
     end
+
+    class UnionDistinct < Binary
+    end
   end
 
   module Visitors
@@ -43,6 +46,11 @@ def visit_Arel_Nodes_ArrayConcat o, collector
           visit o.right, collector
         end
       end
+
+      def visit_Arel_Nodes_UnionDistinct o, collector
+        collector << "( "
+        infix_value(o, collector, " UNION DISTINCT ") << " )"
+      end
     end
   end
-end
+end

spec/active_record/hierarchical_query_spec.rb

@@ -11,6 +11,33 @@
   let!(:child_5) { klass.create(parent: child_4) }
 
   describe '#join_recursive' do
+    describe 'UNION clause' do
+      let(:options) { {} }
+      subject { klass.join_recursive(options) { connect_by(id: :parent_id) }.to_sql }
+
+      it 'defaults to UNION ALL' do
+        expect(subject).to include('UNION ALL')
+      end
+
+      context 'specifying DISTINCT union type' do
+        let(:options) { { union_type: :distinct } }
+
+        it 'uses UNION DISTINCT' do
+          expect(subject).to include('UNION DISTINCT')
+          expect(subject).to_not include('UNION ALL')
+        end
+      end
+
+      context 'specifying ALL union type' do
+        let(:options) { { union_type: :all } }
+
+        it 'uses UNION ALL' do
+          expect(subject).to include('UNION ALL')
+          expect(subject).to_not include('UNION DISTINCT')
+        end
+      end
+    end
+
     describe 'CONNECT BY clause' do
       it 'throws error if CONNECT BY clause not specified' do
         expect {