From: | Stephen Frost <sfrost(at)snowman(dot)net> |
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To: | Hitoshi Harada <umi(dot)tanuki(at)gmail(dot)com> |
Cc: | Peter Eisentraut <peter_e(at)gmx(dot)net>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: Functional dependencies and GROUP BY |
Date: | 2010-06-08 01:38:23 |
Message-ID: | 20100608013823.GI21875@tamriel.snowman.net |
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Lists: | pgsql-hackers |
* Hitoshi Harada (umi(dot)tanuki(at)gmail(dot)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
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