differentiating equality and assignment

1 files changed, 13 insertions, 2 deletions

diff --git a/lib/arel/visitors/to_sql.rb b/lib/arel/visitors/to_sql.rb
index f70cae9430..8638bf43c3 100644
--- a/lib/arel/visitors/to_sql.rb
+++ b/lib/arel/visitors/to_sql.rb
@@ -149,13 +149,24 @@ module Arel
         "#{visit o.left} OR #{visit o.right}"
       end
 
-      def visit_Arel_Nodes_Equality o
+      def visit_Arel_Nodes_Assignment o
         right = o.right
-        # FIXME: maybe we should visit NilClass?
+
         right = right.nil? ? 'NULL' : visit(right)
         "#{visit o.left} = #{right}"
       end
 
+      def visit_Arel_Nodes_Equality o
+        right = o.right
+
+        # FIXME: maybe we should visit NilClass?
+        if right.nil?
+          "#{visit o.left} IS NULL"
+        else
+          "#{visit o.left} = #{visit right}"
+        end
+      end
+
       def visit_Arel_Nodes_UnqualifiedColumn o
         "#{quote_column_name o.name}"
       end