> > I have done initial implementation of SQL99 WITH clause (attached).
> > It's now only for v7.3.4 and haven't a lot of checks and restrictions.
>
> What kind of restrictions are on it?
Main restriction is that the query inside WITH alias can refer only to
back and to itself.
For example
WITH a as (...),b as (...)select ...;
a can refer only to itself, b - to a and b.
Its needed to restrict WITH aliased query not to use WITH aliasing
itself, i.e. avoid situation of WITH inside WITH. And make also some
other checks. But this isn't done yet.
Regards, Evgen.