generate correct select if only offset is present (in Oracle)

lib/arel/visitors/oracle.rb

@@ -40,6 +40,20 @@ module Arel
           return "SELECT * FROM (#{super(o)}) WHERE ROWNUM <= #{limit}"
         end
 
+        if o.offset
+          o        = o.dup
+          offset   = o.offset
+          o.offset = nil
+          sql = super(o)
+          return <<-eosql
+              SELECT * FROM (
+                SELECT raw_sql_.*, rownum raw_rnum_
+                FROM (#{sql}) raw_sql_
+              )
+              WHERE #{visit offset}
+          eosql
+        end
+
         super
       end
 

test/visitors/test_oracle.rb

@@ -105,6 +105,22 @@ module Arel
             sql.must_equal sql2
           end
         end
+
+        describe 'only offset' do
+          it 'creates a select from subquery with rownum condition' do
+            stmt = Nodes::SelectStatement.new
+            stmt.offset = Nodes::Offset.new(10)
+            sql = @visitor.accept stmt
+            sql.must_be_like %{
+              SELECT * FROM (
+                SELECT raw_sql_.*, rownum raw_rnum_
+                FROM (SELECT ) raw_sql_
+              )
+              WHERE raw_rnum_ > 10
+            }
+          end
+        end
+
       end
     end
   end