Optional Pattern
SELECT ?cat ?val ?uri
WHERE (?x rdf:value ?val) (?x category ?cat)
OPTIONAL (?al contains ?x) (?al linkTo ?uri)
- Returns:
["Total Members",100,Res],…,
- But also:
["Full Members",20, ],…,
- (note the empty return value!)
119 (155)
SELECT ?cat ?val ?uri
WHERE (?x rdf:value ?val) (?x category ?cat)
OPTIONAL (?al contains ?x) (?al linkTo ?uri)
["Total Members",100,Res],…,
["Full Members",20, ],…,