diff --git a/lib/redis_counters/dumpers/destination.rb b/lib/redis_counters/dumpers/destination.rb
index c479cb3..97f5090 100644
--- a/lib/redis_counters/dumpers/destination.rb
+++ b/lib/redis_counters/dumpers/destination.rb
@@ -183,7 +183,7 @@ def updating_expression
           case model.columns_hash[field.to_s].type
           when :datetime, :date
             "#{field} = source.#{field}"
-          when :string
+          when :text, :string
             "#{field} = array_to_string(ARRAY[source.#{field}, target.#{field}], '#{delimiter}')"
           else
             "#{field} = COALESCE(target.#{field}, 0) + source.#{field}"
diff --git a/spec/lib/redis_counters/dumpers/engine_spec.rb b/spec/lib/redis_counters/dumpers/engine_spec.rb
index 7daca1b..193cf1b 100644
--- a/spec/lib/redis_counters/dumpers/engine_spec.rb
+++ b/spec/lib/redis_counters/dumpers/engine_spec.rb
@@ -222,6 +222,43 @@
         end
       end
 
+      context 'when incremented field class is text' do
+        let(:dumper) do
+          RedisCounters::Dumpers::Engine.build do
+            name :realtime_stats
+            fields record_id: :integer,
+                   column_id: :integer,
+                   value: :integer,
+                   params: :text,
+                   date: :timestamp
+
+            destination do
+              model RealtimeStat
+              take :record_id, :column_id, :date, :hits, :params
+              key_fields :record_id, :column_id
+              increment_fields :hits, :params
+              map :hits, to: :value
+              condition 'target.date::date = :date::date'
+            end
+          end
+        end
+
+        before do
+          counter.increment(date: date, record_id: 1, column_id: 100, subject: '', params: 'abc')
+          dumper.common_params = {date: date, params: 'abc'}
+          dumper.process!(counter, date: date)
+
+          counter.increment(date: date, record_id: 1, column_id: 100, subject: '', params: 'xyz')
+          dumper.common_params = {date: date, params: 'xyz'}
+          dumper.process!(counter, date: date)
+        end
+
+        it do
+          expect(RealtimeStat.count).to eq 1
+          expect(RealtimeStat.first.params).to eq 'xyz,abc'
+        end
+      end
+
       context 'when incremented field class is date or time' do
         let(:current_time) { Date.today.to_time }
         let(:dumper) do