GROUP_CONCAT problem from Jena

Discussion:

Andy Seaborne

2016-03-28 10:43:54 UTC

Encountered " "distinct" "DISTINCT "" at line 6, column 129

Check the syntax at that point.

(GROUP_CONCAT DISTINCT (?x) ...

is wrong.

Andy

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Andy

Dears,
I've been having this problem since a long time and unfortunately no
one on StackOverFlow could find the solution. It is definitely a bug
in Jena, could you have a look please?
https://stackoverflow.com/questions/36137483/sparql-query-works-on-the-fuseki-interface-but-in-jena

Joshua TAYLOR

2016-03-28 15:27:40 UTC

Permalink

Post by Andy Seaborne
Encountered " "distinct" "DISTINCT "" at line 6, column 129
Check the syntax at that point.
(GROUP_CONCAT DISTINCT (?x) ...
is wrong.

Andy,

I actually started another thread about this (not knowing about this
one), and that error looks like it might on Jena's end. If you throw,
e.g.,

select (group_concat(distinct ?x) as ?y) {}

into the validator on sparql.org, it parses it and formats it as

select (group_concat distinct (?x) as ?y) where {}

If Jena's parsing it and sending the re-formatted query along, the
remote endpoint would complain about the injected syntax error.

Post by Andy Seaborne
Andy

--
Joshua Taylor, http://www.cs.rpi.edu/~tayloj/

Joshua TAYLOR

2016-03-28 15:33:50 UTC

Permalink

Post by Joshua TAYLOR

Post by Andy Seaborne
Encountered " "distinct" "DISTINCT "" at line 6, column 129
Check the syntax at that point.
(GROUP_CONCAT DISTINCT (?x) ...
is wrong.

Andy,
I actually started another thread about this (not knowing about this
one), and that error looks like it might on Jena's end. If you throw,
e.g.,
select (group_concat(distinct ?x) as ?y) {}
into the validator on sparql.org, it parses it and formats it as
select (group_concat distinct (?x) as ?y) where {}
If Jena's parsing it and sending the re-formatted query along, the
remote endpoint would complain about the injected syntax error.

Is it significant that

https://github.com/apache/jena/blob/0653392c24d6ec0d83c97c77f789a85b3c3b79de/jena-arq/src/main/java/org/apache/jena/sparql/expr/aggregate/AggGroupConcat.java#L71

appends a group_concat with a following (, whereas

https://github.com/apache/jena/blob/0653392c24d6ec0d83c97c77f789a85b3c3b79de/jena-arq/src/main/java/org/apache/jena/sparql/expr/aggregate/AggGroupConcat.java#L91

doesn't?

Post by Joshua TAYLOR

Post by Andy Seaborne
Andy

--
Joshua Taylor, http://www.cs.rpi.edu/~tayloj/

Andy Seaborne

2016-03-28 16:51:57 UTC

Permalink

Post by Joshua TAYLOR

Post by Andy Seaborne
Encountered " "distinct" "DISTINCT "" at line 6, column 129
Check the syntax at that point.
(GROUP_CONCAT DISTINCT (?x) ...
is wrong.

Andy,
I actually started another thread about this (not knowing about this
one), and that error looks like it might on Jena's end. If you throw,
e.g.,
select (group_concat(distinct ?x) as ?y) {}
into the validator on sparql.org, it parses it and formats it as
select (group_concat distinct (?x) as ?y) where {}
If Jena's parsing it and sending the re-formatted query along, the
remote endpoint would complain about the injected syntax error.

Is it significant that
https://github.com/apache/jena/blob/0653392c24d6ec0d83c97c77f789a85b3c3b79de/jena-arq/src/main/java/org/apache/jena/sparql/expr/aggregate/AggGroupConcat.java#L71
appends a group_concat with a following (, whereas
https://github.com/apache/jena/blob/0653392c24d6ec0d83c97c77f789a85b3c3b79de/jena-arq/src/main/java/org/apache/jena/sparql/expr/aggregate/AggGroupConcat.java#L91
doesn't?

Hi Joshua,

Thanks for taking the time to investigate.

Good news - this is a fixed bug.
https://issues.apache.org/jira/browse/JENA-1091

so it is not in 3.0.1 release, getting fix on the day of the release, 3
days after the build.

asSparqlExpr is the method that creates SPARQL syntax:
and it says:

x.append("GROUP_CONCAT(") ;
if ( isDistinct )
x.append("DISTINCT ") ;

so it is GROUP_CONCAT(DISTINCT ...) now.

prefixGroupConcatString creates syntax for the algebra form.

sparql.org is not up-to-date - unfortunately that machine (it's part of
the Apache infrastructure and a FreeBSD host machine running with jails
to isolate services) does not have an installable Java8 so it is not
up-to-date. It needs migrating sometime.

Andy

The OP is currently bombarding the users@ moderator with emails due to
not subscribing.

Post by Joshua TAYLOR

Post by Andy Seaborne
Andy

--
Joshua Taylor, http://www.cs.rpi.edu/~tayloj/

Joshua TAYLOR

2016-03-28 17:09:09 UTC

Permalink

Post by Andy Seaborne
Hi Joshua,
Thanks for taking the time to investigate.
Good news - this is a fixed bug.
https://issues.apache.org/jira/browse/JENA-1091

Great!

Post by Andy Seaborne
subscribing.

That's unfortunate. I'm not quite sure that the OP understands
exactly what mailing lists are [1].

[1] http://stackoverflow.com/questions/36137483/sparql-query-works-on-the-fuseki-interface-but-in-jena/36261611?noredirect=1#comment60159162_36261611

--
Joshua Taylor