Merge pull request #410 from kbrock/concat

Add database specific string concatenation

5 files changed, 20 insertions, 1 deletions

diff --git a/lib/arel/nodes/infix_operation.rb b/lib/arel/nodes/infix_operation.rb
index 3911a1e05e..a3f04da6fa 100644
--- a/lib/arel/nodes/infix_operation.rb
+++ b/lib/arel/nodes/infix_operation.rb
@@ -40,5 +40,10 @@ module Arel
       end
     end
 
+    class Concat < InfixOperation
+      def initialize left, right
+        super('||', left, right)
+      end
+    end
   end
-end
\ No newline at end of file
+end
diff --git a/lib/arel/predications.rb b/lib/arel/predications.rb
index e9078e9c4b..81bf3b4d95 100644
--- a/lib/arel/predications.rb
+++ b/lib/arel/predications.rb
@@ -202,6 +202,10 @@ Passing a range to `#not_in` is deprecated. Call `#not_between`, instead.
       Nodes::Case.new(self).when quoted_node(right)
     end
 
+    def concat other
+      Nodes::Concat.new self, other
+    end
+
     private
 
     def grouping_any method_id, others, *extras
diff --git a/lib/arel/visitors/depth_first.rb b/lib/arel/visitors/depth_first.rb
index 2f71455580..fb21fb1e70 100644
--- a/lib/arel/visitors/depth_first.rb
+++ b/lib/arel/visitors/depth_first.rb
@@ -72,6 +72,7 @@ module Arel
       alias :visit_Arel_Nodes_As                 :binary
       alias :visit_Arel_Nodes_Assignment         :binary
       alias :visit_Arel_Nodes_Between            :binary
+      alias :visit_Arel_Nodes_Concat             :binary
       alias :visit_Arel_Nodes_DeleteStatement    :binary
       alias :visit_Arel_Nodes_DoesNotMatch       :binary
       alias :visit_Arel_Nodes_Equality           :binary
diff --git a/lib/arel/visitors/dot.rb b/lib/arel/visitors/dot.rb
index e0c02d717a..da75423523 100644
--- a/lib/arel/visitors/dot.rb
+++ b/lib/arel/visitors/dot.rb
@@ -176,6 +176,7 @@ module Arel
       alias :visit_Arel_Nodes_As                 :binary
       alias :visit_Arel_Nodes_Assignment         :binary
       alias :visit_Arel_Nodes_Between            :binary
+      alias :visit_Arel_Nodes_Concat             :binary
       alias :visit_Arel_Nodes_DoesNotMatch       :binary
       alias :visit_Arel_Nodes_Equality           :binary
       alias :visit_Arel_Nodes_GreaterThan        :binary
diff --git a/lib/arel/visitors/mysql.rb b/lib/arel/visitors/mysql.rb
index 724e0fc43e..ac3ad7b470 100644
--- a/lib/arel/visitors/mysql.rb
+++ b/lib/arel/visitors/mysql.rb
@@ -72,6 +72,14 @@ module Arel
         maybe_visit o.limit, collector
       end
 
+      def visit_Arel_Nodes_Concat o, collector
+        collector << " CONCAT("
+        visit o.left, collector
+        collector << ", "
+        visit o.right, collector
+        collector << ") "
+        collector
+      end
     end
   end
 end