Merge pull request #432 from tradegecko/pg-grouping-elements-support

PG: Add Support for GroupBy's Cube, Rollup and Grouping Set

1 files changed, 36 insertions, 0 deletions

diff --git a/lib/arel/visitors/postgresql.rb b/lib/arel/visitors/postgresql.rb
index 1ef0261bdd..ef0f0ea2ef 100644
--- a/lib/arel/visitors/postgresql.rb
+++ b/lib/arel/visitors/postgresql.rb
@@ -1,6 +1,10 @@
 module Arel
   module Visitors
     class PostgreSQL < Arel::Visitors::ToSql
+      CUBE = 'CUBE'
+      ROLLUP = 'ROLLUP'
+      GROUPING_SET = 'GROUPING SET'
+
       private
 
       def visit_Arel_Nodes_Matches o, collector
@@ -43,6 +47,38 @@ module Arel
       def visit_Arel_Nodes_BindParam o, collector
         collector.add_bind(o) { |i| "$#{i}" }
       end
+
+      def visit_Arel_Nodes_GroupingElement o, collector
+        collector << "( "
+        visit(o.expr, collector) << " )"
+      end
+
+      def visit_Arel_Nodes_Cube o, collector
+        collector << CUBE
+        grouping_array_or_grouping_element o, collector
+      end
+
+      def visit_Arel_Nodes_RollUp o, collector
+        collector << ROLLUP
+        grouping_array_or_grouping_element o, collector
+      end
+
+      def visit_Arel_Nodes_GroupingSet o, collector
+        collector << GROUPING_SET
+        grouping_array_or_grouping_element o, collector
+      end
+
+      # Utilized by GroupingSet, Cube & RollUp visitors to
+      # handle grouping aggregation semantics
+      def grouping_array_or_grouping_element o, collector
+        if o.expr.is_a? Array
+          collector << "( "
+          visit o.expr, collector
+          collector << " )"
+        else
+          visit o.expr, collector
+        end
+      end
     end
   end
 end