Items that have names after them in the TODO-list, do these names indicate
that the persons are working on it now?
The item i'm extra curious about is
* Add SQL99 WITH clause to SELECT (Tom, Fernando)
There is also an item for handling recursive such clauses.
The simple non recursive case can be implemented in a straight forward
(but stupid) way, where one "just" substitute in for the variables. It
won't give any sharing effects that one can get by declaring a variable
once and use it several times. It will however make it much easier to
write readable SQL expressions. The sharing can be seen as just an
optimization anyway.
Also, it's not at all clear to me how to decide when one want to calculate
the subexpression first and use in the other places and when to duplicate
the expression to let the optimizer work with it. I however just want it
in order to make my SQL-code simpler and more expressive.
Maybe I should also point out that I have not implemented this so I can't
be sure that it really is just as simple as just substituting. It looks
like it after a quick look, that's all!
--
/Dennis