good morning, > On 2015-07-03, at 04:51, Jeremy J Carroll <j...@syapse.com> wrote: > > Yes this text seems to be in tension with 11.4 > http://www.w3.org/TR/2013/REC-sparql11-query-20130321/#aggregateRestrictions > In a query level which uses aggregates, only expressions consisting of > aggregates and constants may be projected > > I guess it may be talking about the exception, the variables in the GROUP BY > itself, which would be treated correctly by replacing with a SAMPLE() > aggregation, since in each group the values of the group by variable are > always the same, and SAMPLE of the multiset of values is just the value > itself. > > Jeremy > > >> On Jul 2, 2015, at 9:12 AM, Matthew Horridge <matthew.horri...@stanford.edu> >> wrote: >> >> Hi, >> >> I’ve been reading through the definition of SPARQL in the SPARQL 1.1. Query >> Language Document. In particular, section 18.2.4, which describes how to >> convert aggregate queries into the SPARQL algebra. >> >> The algorithm listed in 18.2.4.1, which I’ve pasted in below talks about >> “unaggregated variables”. However, there isn’t a definition for >> “unaggregated variable” in the spec, and it isn’t totally clear to me what >> an “unaggregated variable” is. If anyone could provide me with a precise >> definition for what an “unaggregated variable” is, and thus clarify this >> part of the spec, I would really appreciate it. >> >> Thanks a lot, >> >> Matthew >> >> >> >> >> >> For each (X AS Var) in SELECT, each HAVING(X), and each ORDER BY X in Q
given this text and the phrase, "replacing aggregate expressions”, above, “unaggregated variable” is not a defined term, as such, but rather applies to any “X” which is not an aggregate expression, that is, which is just a variable. >> For each unaggregated variable V in X >> Replace V with Sample(V) >> End >> For each aggregate R(args ; scalarvals) now in X >> # note scalarvals may be omitted, then it's equivalent to the empty set >> A >> i >> := Aggregation(args, R, scalarvals, G) >> Replace R(...) with agg >> i >> in Q >> i := i + 1 >> End >> End >> >> > best regards, from berlin, --- james anderson | ja...@dydra.com | http://dydra.com
