[Documentation]: DQL requires a specific order when using @count with @recurse #461
Description
What version of Dgraph is the target?
v21.03.01
Documentation.
DQL requires a specific order when using @count with @recurse. The below examples illustrate the behavior based on DGraph Tour examples.
The @count documentation page should reflect the changed/abnormal behavior when used in conjunction with @recurse.
When returning a Predicate AND counting the same Predicate - the DQL Query must have the @count(predicate) ordered below the predicate in the DQL query.
The below examples can be replicated by following the steps 1-6 in the DGraph Tour: Graphs | Intro | Dgraph Tour
The query returns wrong data:
Note: The count of friend is above the predicate friend
{
michael(func: eq(name, "Michael")) @recurse(depth:10){
name
age
owns_pet
friend~
count(friend @filter(NOT eq(name, "Sarah")))
friend @filter(NOT eq(name, "Sarah"))
}
}
The query returns correct data:
Note: The count of friend is below the predicate friend
{
michael(func: eq(name, "Michael")) @recurse(depth:10){
name
age
owns_pet
friend~
friend @filter(NOT eq(name, "Sarah"))
count(friend @filter(NOT eq(name, "Sarah")))
}
}
Details are in this discuss post: https://discuss.dgraph.io/t/does-order-in-a-dql-query-matter/18274/4
Additional information.
I honestly think this is a bug as well. The discus post had some conversation about what is correct vs. incorrect behavior of DGraph. I think at least DGraph should throw an error stating you can't put a count above a predicate when counting the same predicate. Ideally, the order of where the count is in the DQL shouldn't matter.