Query Help: Summarising paths

MichelDiz · October 4, 2020, 8:03pm

So basically your issue is just like this one Aggregating facet variables
See my last comment there.

Also see this example

github.com/dgraph-io/dgraph

Sum over facets is incorrect

opened 10:27PM - 11 Oct 19 UTC

closed 04:52AM - 21 Jul 20 UTC

campoy

kind/bug priority/P1 status/accepted area/facets

## What version of Dgraph are you using? master ### Have you tried reprodu…cing the issue with the latest release? yes ### What is the hardware spec (RAM, OS)? n/a ### Steps to reproduce the issue (command/config used to run Dgraph). Given the dataset generated by this mutation: ```rdf { set { _:a <name> "Anne" . _:b <name> "Brian" . _:jp <name> "Jurassic Park" . _:ij <name> "Indiana Jones" . _:a <rated> _:jp (rating=5) . _:a <rated> _:ij (rating=2) . _:b <rated> _:ij (rating=2) . } } ``` If you run the following request: ```graphql { q(func: has(rated)) { name rated @facets(r as rating) partial_sum: sum(val(r)) } sum() { total_sum: sum(val(r)) } } ``` ### Expected behaviour and actual result. I'd expect `partial_sum` to be 7 for Anne and 2 for Brian, then `total_sum` would be 9. Instead, the result is as follows: ```json { "data": { "q": [ { "name": "Anne", "rated": [ { "rated|rating": 5 }, { "rated|rating": 2 } ], "partial_sum": 9 }, { "name": "Brian", "rated": [ { "rated|rating": 2 } ], "partial_sum": 4 } ], "sum": [ { "total_sum": 9 } ] } } ``` I have a theory about why we're getting these weird numbers. Variables attach values to uid, but in this case that's not the right behavior, as the value of the variable should not be attached to the UID of the person nor the movie, but rather the combination of both linked by the predicate. You can see the weird artifact by querying by this value on all of the nodes. ```graphql { var(func: has(rated)) { rated @facets(r as rating) } sum(func: has(name)) { name val(r) } } ``` returns ```json { "data": { "sum": [ { "name": "Jurassic Park", "val(r)": 5 }, { "name": "Indiana Jones", "val(r)": 4 }, { "name": "Anne" }, { "name": "Brian" } ] } } ``` This proves that the variable `r` has been attached to the movie UIDs by adding all of the values in the facets pointing to them. Once we understand this, it makes sense that the sum of the ratings for Anne is 9 instead of 7, as it's the sum of the ratings for the two movies. Same goes for the ratings for Brian being 4 instead of 2. Fixing this might be complicated, as it might imply making variables work as a map from <uid, uid> to value rather than <uid> to value.

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Query Help: Summarising paths

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