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[Bug 10733] New: [XQuery11] Definition of group by expression not sufficent

From: <bugzilla@jessica.w3.org>
Date: Fri, 24 Sep 2010 18:15:18 +0000
To: public-qt-comments@w3.org
Message-ID: <bug-10733-523@http.www.w3.org/Bugs/Public/>
http://www.w3.org/Bugs/Public/show_bug.cgi?id=10733

           Summary: [XQuery11] Definition of group by expression not
                    sufficent
           Product: XPath / XQuery / XSLT
           Version: Member-only Editors Drafts
          Platform: PC
        OS/Version: Windows NT
            Status: NEW
          Severity: normal
          Priority: P2
         Component: XQuery 1.1
        AssignedTo: jonathan.robie@redhat.com
        ReportedBy: oliver@cbcl.co.uk
         QAContact: public-qt-comments@w3.org


3.9.7 says:

The input tuple stream is partitioned into groups of tuples whose grouping keys
are equivalent.

As far as I can tell, it is legal for a processor to implement group by as a
no-op!

By returning all the input tuples separately you have indeed partitioned them
into groups of (single) tuples whose grouping keys are equivalent.

There needs to be some sentence indicating when two items must be in the same
group.    The distinct-values function is very careful to define this (F&O
14.1.2):

If the input sequence contains values of different numeric types that differ
from each other by small amounts, then the eq operator is not transitive,
because of rounding effects occurring during type promotion. In the situation
where the input contains three values A, B, and C such that A eq B, B eq C, but
A ne C, then the number of items in the result of the function (as well as the
choice of which items are returned) is implementation-dependent, subject only
to the constraints that (a) no two items in the result sequence compare equal
to each other, and (b) every input item that does not appear in the result
sequence compares equal to some item that does appear in the result sequence.

and much of this wording could be copied for the definition here.

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Received on Friday, 24 September 2010 18:15:20 GMT

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