I have query with sub queries. I need to create materialized view with fast refresh. I understood that it is not possible to create materialized view with sub queries. While googling someone suggested to create a view and then create materialized view on the view, but few mentioned it is not good option since fast refresh will not happen. The approach came to my mind is create materialized views for sub queries and build a main materialized view using them. Is this a good idea. I like to know are there any issues I will face with this approach especially fast refresh. Up on commit in base tables whether the changes propagate from lower level materialized views to the one using them.