Sparql Construct statement containing count(?var) - sparql

Question

data.ttl:
#base <http://example.org/> .
#prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
#prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
#prefix : <http://example.org/#> .
:Bob a :Student;
:tookTest :Test0,:Test1,:Test2, :Test3, :Test4, :Test5, :Test6, :Test7, :Test8, :Test9.
:Test0 :grade "A" .
:Test1 :grade "A" .
:Test2 :grade "A" .
:Test3 :grade "A" .
:Test4 :grade "A" .
:Test5 :grade "A" .
:Test6 :grade "A" .
:Test7 :grade "B" .
:Test8 :grade "C" .
:Test9 :grade "D" .
sparql query:
PREFIX : <http://example.org/#>
SELECT ?student ?grade (count(?grade) as ?count)
WHERE {
?student :tookTest ?test .
?test :grade ?grade .
}
GROUP BY ?student ?grade
order by ?grade
I get result like follows:
student, grade, count
http://example.org/#Bob,A,7
http://example.org/#Bob,B,1
http://example.org/#Bob,C,1
http://example.org/#Bob,D,1
Now how can I get the same result with Construct?
I used the following query statement, but I didn't get any expected results:
PREFIX : <http://example.org/#>
CONSTRUCT {?student ?grade ?count .}
WHERE {
SELECT ?student ?grade (count(?grade) as ?count)
WHERE {
?student :tookTest ?test .
?test :grade ?grade .
}
GROUP BY ?student ?grade
}
How do I write this Sparql CONSTRUCT statement correctly?
Thanks in advance for help.

Answer 1

I got it done.
replace all "A" with :A , so do with "B", "C", "D".
then everything is OK.