Add support for polymorphic table functions (https://www.iso.org/standard/69776.html)
How's it going now?
I guess this would be like MSSQL 'Linked Server' functionality: https://docs.microsoft.com/en-us/sql/t-sql/functions/openquery-transact-sql?view=sql-server-ver15 / https://docs.microsoft.com/en-us/sql/relational-databases/linked-servers/linked-servers-database-engine?view=sql-server-ver15
Most helpful comment
How's it going now?