Re: Functional dependencies and GROUP BY

* Hitoshi Harada (umi.tanuki@gmail.com) wrote:
> I don't see why it should be allowed. I see the insist that y must be
> unique value so it is ok to be ungrouped but the point of discussion
> is far from that; Semantically y is not grouping key.

Ignoring the fact that it's terribly useful- isn't it part of the SQL
spec?

> In addition, what if y is implicitly a constant? For example,
>
> SELECT x, y FROM tab2 WHERE y = a AND a = 5 GROUP BY x;

Not sure I see the issue here?

> Finally, it may hide unintended bugs. ORM tools may make WHERE clause
> in some conditions and don't in other conditions.

Yeah, this one I really just done buy..  If an ORM tool doesn't write
correct SQL, then it's the ORM's fault, not ours.
Thanks,
    Stephen