Support for COUNT(*)

[tholiebig]

The query parser seems to not support COUNT(*). Is there a timetable for resolving this problem?
PS: I also vote for adding FILTER NOT EXISTS to clever.

[joka921]

Hi,
PR #1411 Will add support for COUNT([DISTINCT] *). It is already running on our public wikidata endpoint. Not that there is currently a bug that shows too large results for the DISTINCT case when the query contains a property path. This has already been fixed, but not yet deployed to the endpoint.
You can expect this to be merged some time next week hopefully.

FILTER NOT EXISTS is somewhere on the list (currently thinking about the correct semantics and an efficient implementation), but we do not have an estimated time frame for this.

[tholiebig]

That's great news. Thank you this information. Please keep me posted about FILTER NOT EXISTS.

[tholiebig]

Hi, thanks again for supporting this.
However, I couldn't get it to work:

> qlever --version
qlever 0.5.6

> curl -s localhost:7019 -H "Accept: text/tab-separated-values" --data-urlencode query='SELECT (count (distinct *) as ?cnt) WHERE { ?s ?p ?o } LIMIT 10'
{
    "exception": "Invalid SPARQL query: This parser currently doesn't support COUNT(*), please specify an explicit expression for the COUNT",
    "metadata": {
        "line": 1,
        "positionInLine": 8,
        "query": "SELECT (count (*) as ?cnt) WHERE { ?s ?p ?o } LIMIT 10",
        "startIndex": 8,
        "stopIndex": 16
    },
    "query": "SELECT (count (*) as ?cnt) WHERE { ?s ?p ?o } LIMIT 10",
    "resultsize": 0,
    "status": "ERROR",
    "time": {
        "computeResult": 2,
        "total": 2
    }
}

Any hints?

[hannahbast]

@tholiebig It looks like you are using an old version of QLever. Are you using Docker? Then make sure that you pull the latest version with docker pull adfreiburg/qlever.

[tholiebig]

Yes, that did it. Thanks @hannahbast I suggest to add this to the usage description.