Fusion for MySQL offers full support for subqueries in all SELECT statement clauses. Each subquery can have its own subqueries.
When you create a subquery or open it for visual editing, a subquery tab of the query document appears. This offers you simple navigating subqueries using these tabs. You can navigate to the upper-level query from the subquery with the Parent Query button on the Devart - Query toolbar. You can also use the Document Outline window to navigate the complex queries.
If you want to include a table along with joins, conditions, and subqueries into a subquery, you have to set focus on the whole diagram area instead of the particular table and perform the Wrap to Subquery operation for your diagram.