Allow INSERT INTO <table> SELECT queries

3 files changed, 16 insertions, 3 deletions

diff --git a/lib/arel/insert_manager.rb b/lib/arel/insert_manager.rb
index b5d2aeb3a4..8839dd8181 100644
--- a/lib/arel/insert_manager.rb
+++ b/lib/arel/insert_manager.rb
@@ -13,6 +13,10 @@ module Arel
     def columns; @ast.columns end
     def values= val; @ast.values = val; end
 
+    def select select
+      @ast.select = select
+    end
+
     def insert fields
       return if fields.empty?
 
diff --git a/lib/arel/nodes/insert_statement.rb b/lib/arel/nodes/insert_statement.rb
index ec8870a1c2..ada4fcc562 100644
--- a/lib/arel/nodes/insert_statement.rb
+++ b/lib/arel/nodes/insert_statement.rb
@@ -1,29 +1,32 @@
 module Arel
   module Nodes
     class InsertStatement < Arel::Nodes::Node
-      attr_accessor :relation, :columns, :values
+      attr_accessor :relation, :columns, :values, :select
 
       def initialize
         super()
         @relation = nil
         @columns  = []
         @values   = nil
+        @select   = nil
       end
 
       def initialize_copy other
         super
         @columns = @columns.clone
         @values =  @values.clone if @values
+        @select =  @select.clone if @select
       end
 
       def hash
-        [@relation, @columns, @values].hash
+        [@relation, @columns, @values, @select].hash
       end
 
       def eql? other
         self.class == other.class &&
           self.relation == other.relation &&
           self.columns == other.columns &&
+          self.select == other.select &&
           self.values == other.values
       end
       alias :== :eql?
diff --git a/lib/arel/visitors/to_sql.rb b/lib/arel/visitors/to_sql.rb
index e1b46eb6e6..22f7943ab9 100644
--- a/lib/arel/visitors/to_sql.rb
+++ b/lib/arel/visitors/to_sql.rb
@@ -127,7 +127,13 @@ module Arel
           }.join ', '})"
         end
 
-        maybe_visit o.values, collector
+        if o.values
+          maybe_visit o.values, collector
+        elsif o.select
+          maybe_visit o.select, collector
+        else
+          collector
+        end
       end
 
       def visit_Arel_Nodes_Exists o, collector