Wt

Since WITH is supported over nearly all Dbo backends, we can integrate that in Wt::Dbo as well.
See: https://modern-sql.com/feature/with#compatibility

Firebird is not part of this overview but ought to support it too: https://firebirdsql.org/rlsnotesh/rnfb210-dml.html#rnfb210-cte
This may require an upgrade of IBPP.

The WITH clause allows for common table expressions to be defined, which allows queries to be more dynamic, and recursive.