On 12/07/2007, at 9:58 PM, Ken Anderson wrote:
Actually, Sybase will accept the query. It allows group by on
fields that are not in the select.
Grouping by fields not used in the select clause is not strictly
legal SQL either (I don't think), and I can't think of a case you
would actually want to do that off hand, but even so the result
should be deterministic. The issue I am referring to is attempting to
select from fields that aren't in the group by clause. If your
database accepts this syntax, it's broken. The reason being that the
result is non-determinate because you are asking the database to
aggregate a set of possible results into a single value without any
selection criteria.
Consider the case where the previously mentioned table had a
middleName field. If you were to SELECT * ... GROUP BY departmentId,
and there are two Bob Smith's with different middle names in a single
department, which middle name should be returned?
On Jul 12, 2007, at 2:55 AM, Q wrote:
This query is invalid, your database should reject it.
It should be:
SELECT departmentId FROM foo WHERE lastName='Smith' AND
firstName='Bob' GROUP BY departmentId
which is the same as writing:
SELECT DISTINCT departmentId FROM foo WHERE lastName='Smith' AND
firstName='Bob'
--
Seeya...Q
Quinton Dolan - [EMAIL PROTECTED]
Gold Coast, QLD, Australia (GMT+10)
Ph: +61 419 729 806
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