SPARQL concat plus group_concat on multiple fields

Question

I have the following RDF structure that I cannot change:

Multiple Assignments can be associated to each employee (Manager). The output I'd like would be (including the word "in" and "&):

Employee Name   | Assignment

Name 1          | Assignment1 in Location1 & Assignment2 in Location2 &....
Name 2          | Assignment1 in Location2 & Assignment3 in Location1 &....

Is there a way to do this in Sparql?

This is what I have so far:

select ?name group_concat(DISTINCT ?description; separator("&"))
where
{
  ?employee :hasName ?name
  {
  select concat(?name, "In", ?location)
  ?employee ^:hasManager/:hasAsstName ?name
  ?employee ^:hasManager/:hasLocation ?location
  }

}

This gives me empty employee name and lots of ?Descriptions. It does not seem to reflect what I was expecting.

Answer 1

Assuming the nested query is fine, you should assign a variable there to group concatenate and then group the results for all not concatenated variables. The query should look something like this:

select ?name (group_concat(DISTINCT ?description; separator = " & ") as ?descriptions)
where
{
  ?employee :hasName ?name
  {
  select (concat(?name, " in ", ?location) AS ?description)
  ?employee ^:hasManager/:hasAsstName ?name
  ?employee ^:hasManager/:hasLocation ?location
  }

}

GROUP BY ?name

Note the syntax for GROUP_CONCAT.

If you remove the subquery, it will be much faster. As I don't have your data, here's a very similar query on DBpedia, not using subquery:

SELECT ?name (GROUP_CONCAT(DISTINCT ?SpouseInfo; separator = " & ") AS ?SpousesInfo)

{
    ?name a foaf:Person;
    dbo:spouse ?spouse.
    ?spouse dbo:residence/rdfs:label ?residence;
    rdfs:label ?spouse_name

    BIND (CONCAT(?spouse_name, " lives in ",?residence) AS ?SpouseInfo)
}
GROUP BY ?name
ORDER BY ?name

LIMIT 100

Here's the result.