Allow count nodes to have math functions

2 files changed, 11 insertions, 0 deletions

diff --git a/lib/arel/nodes/count.rb b/lib/arel/nodes/count.rb
index a7c6236a22..4dd9be453f 100644
--- a/lib/arel/nodes/count.rb
+++ b/lib/arel/nodes/count.rb
@@ -2,6 +2,8 @@
 module Arel
   module Nodes
     class Count < Arel::Nodes::Function
+      include Math
+
       def initialize expr, distinct = false, aliaz = nil
         super(expr, aliaz)
         @distinct = distinct
diff --git a/test/nodes/test_count.rb b/test/nodes/test_count.rb
index 85e93b1927..29883df681 100644
--- a/test/nodes/test_count.rb
+++ b/test/nodes/test_count.rb
@@ -31,4 +31,13 @@ describe Arel::Nodes::Count do
       assert_equal 2, array.uniq.size
     end
   end
+
+  describe 'math' do
+    it 'allows mathematical functions' do
+      table = Arel::Table.new :users
+      (table[:id].count + 1).to_sql.must_be_like %{
+        (COUNT("users"."id") + 1)
+      }
+    end
+  end
 end