[Tarantool-patches] [PATCH] rfc: multi-directional iterators

[Konstantin Osipov]

* Aleksandr Lyapunov <alyapunov at tarantool.org> [20/04/24 13:11]:
> > +may want to select tuples with `a >= 1`, `b >= 1` but `c < 1`. Or, alternatively,
> > +somebody may be willing to get tuples ordered by `a` and `b` in ascending order
> > +but by `c` in descending order: `i:select({}, {iterator = {'GE', 'GE', 'LE'})`.
> Those are not alternatives but independent options. One may wish to select:
> `SELECT * FROM t WHERE a > 1 AND b < 1 ORDER BY a DESC, b ASC`.

I agree. 

> My summary:
> 
> 1. `select({1, 1}, {iterator='GE'})` is not equivalent to `SELECT ..
>    WHERE a>=1 AND b >= 1`.
> 2. It is still possible to implement `iterator={'GE', 'GE'}` that will
>    suitable for that SQL SELECT.
> 3. It is also possible to implement `order={'ASC', 'DESC'}` option in
>    select using the solution #1.

I agree, but it's not urgent either. These queries are rare.

-- 
Konstantin Osipov, Moscow, Russia