- From: Lee Feigenbaum <lee@thefigtrees.net>
- Date: Wed, 03 Feb 2010 08:42:56 -0500
- To: Andy Seaborne <andy.seaborne@talis.com>
- CC: SPARQL Working Group <public-rdf-dawg@w3.org>
Thanks, Andy. This is very helpful. I've excerpted just the ones I have comments on. Andy Seaborne wrote: > Here is my recollection of the status of query related open issues. > > ?? for still unresolved. > > DONE, for where I think we have agreement or proposal to go in the doc. > > Andy > > ISSUE-5 > ASK queries in FILTERs > ?? (related -- EXISTS in FILTERS) > > ISSUE-6 > SELECT queries in FILTERs > ?? > > ISSUE-7 > CONSTRUCT & DESCRIBE queries in FROM [NAMED]? > ?? > CONSTRUCT not needed if bNodes can be introduced by constructor. > ISSUE-13 > Subqueries in HAVING analogous to subqueries in FILTERs > ?? > ** Related to ISSUE-6 > There was consensus from the people at F2F2 to not include any subqueries other than SELECT in graph patterns. I see EXISTS in FILTERs as being the only outstanding question here. > ISSUE-29 > Should negation be done via a binary operator on subqueries, a binary > operator within graph patterns, or a filter+subquery? > ?? > This is MINUS / NOT EXISTS issue. This might be a good place to start with a test case or three. Andy, do you happen to have any cases that illustrate the difference here? (I know that personally, my preference here is pretty much "no preference".) > ISSUE-35 > Can aggregate functions take DISTINCT as an argument a la SELECT > COUNT(DISTINCT ?X)? > > DONE All built-in aggregates can take the word DISTINCT. > Custom ones do not; it's part of their definition, > i.e. different URIs for a DISTINCT and non DISTINCT form. I'm with Steve here; I didn't realize this had been decided. FWIW, Glitter supports DISTINCT in custom aggregates too, but I wouldn't lay down in the road over it being in the standard. > ISSUE-41 > Does GROUP BY allow variables or expressions, and does it allow mutiple > expressions? > ?? > (I hope it does - it's just key calculation) The question here from F2F2 was in the interplay between this and requiring that all non-scalar expressions that are projected be in the GROUP BY clause. The question(s) that needed answering were things like: A) What if I do "SELECT (?x + ?y AS ?sum)" and then do "GROUP BY (?y + ?x)"? B) What if I do "SELECT (?x + ?y AS ?sum)" and then do "GROUP BY (?x+?y)"? ...basically, how is expression identity handled. Lee
Received on Wednesday, 3 February 2010 13:43:36 UTC