diff --git a/project_task_actual_report/reports/project_task_actual_report.py b/project_task_actual_report/reports/project_task_actual_report.py
index 382174d..302d975 100644
--- a/project_task_actual_report/reports/project_task_actual_report.py
+++ b/project_task_actual_report/reports/project_task_actual_report.py
@@ -263,42 +263,53 @@ def _get_partitioned_data_from(self):
     @api.model
     def _get_filled_data_query(self):
         """Fill empty values in rows with previous value."""
-        # Second part ot the idea coming from
-        # https://stackoverflow.com/a/19012333/11534960
-        return """select
-    message_id as id,
-    task_id,
-    message_id,
-    date,
-    case when new_name <> old_name -- Change counts as old value
-    then old_name
-    else first_value(new_name)
-        over (partition by task_id, count_new_name order by message_id)
-    end "name",
-    case when new_user_id <> old_user_id
-    then old_user_id
-    else first_value(new_user_id)
-        over (partition by task_id, count_new_user_id order by message_id)
-    end user_id,
-    case when new_stage_id <> old_stage_id
-    then old_stage_id
-    else first_value(new_stage_id)
-        over (partition by task_id, count_new_stage_id order by message_id)
-    end stage_id,
-    case when new_kanban_state <> old_kanban_state
-    then old_kanban_state
-    else first_value(new_kanban_state)
-        over (partition by task_id, count_new_kanban_state order by message_id)
-    end kanban_state,
-    lag(date) over (partition by task_id order by date) as prev_update,
-    extract(epoch from
-        (date - lag(date)
-            over (partition by task_id order by date)))/ 3600 as duration
+        return """
+{select_clause}
 from ({partitioned_data}) partitioned_data
 """.format(
+            select_clause=self._get_filled_data_select(),
             partitioned_data=self._get_partitioned_data_query(),
         )
 
+    def _get_filled_data_select(self):
+        """
+        Select duration of changes using partitions.
+
+        For each tracked field, use a partition over the task id
+        to record the time passed
+        from the last change of any other tracked field.
+        Ordering of partitions is the date of the change.
+        Some other fields useful for the context
+        like message_id and task_id are selected.
+        `message_id` is used as this table's id.
+        """
+        # Second part ot the idea coming from
+        # https://stackoverflow.com/a/19012333/11534960
+        select_clause = ["""select
+message_id as id,
+task_id,
+message_id,
+date,
+lag(date) over (partition by task_id order by date) as prev_update,
+extract(epoch
+        from (date - lag(date)
+        over (partition by task_id order by date)))
+/ 3600
+as duration
+            """]
+        for field_name in TRACKED_TASK_FIELDS:
+            field_select = """
+case when new_{field_name} <> old_{field_name} -- Change counts as old value
+then old_{field_name}
+else first_value(new_{field_name})
+     over (partition by task_id, count_new_{field_name} order by message_id)
+end
+"{field_name}"
+            """.format(field_name=field_name)
+            select_clause.append(field_select)
+        select_clause = ', '.join(select_clause)
+        return select_clause
+
     @api.model
     def _get_cleaned_data_query(self):
         """Clan data that are not interesting.