OrientDB SQL - traverse while keeping edges weight - orientdb

Question

Lets assume the following model in OrientDB graph:
I have a Profile vertex.
Profiles are connected with 2 edges: Liked and Commented. Both edges have a "value" field indicating the count of the action (or the "weight" of the edge).
So, if user A commented 3 times on posts by user B there will be a Commented edge from user A to user B with value = 3.
Now, say I want to get all the users that interacted with user B (either liked or commented), sorted by the weight of the interaction.
I can do that with the following SQL:
select * from (traverse out from
(select out, sum(value) as value from
(traverse * from (select from Profile where username="B") while $depth < 3)
where #class="Liked" or #class="Commented" group by out order by value desc)
while $depth < 2 ) where #class="Profile" )
But what if I want to know also the weight of the interaction? How do I propagate up the "value" while doing the last traverse?
Edit
According to the suggestion, a simplified version of this query will be:
select expand(out) from (
select out, sum(value) as value from (
select expand(inE("Liked", "Commented")) from Profile
where username="B"
) group by out order by value desc
)
But I still can't find a way to use LET to insert the value into the outer expanded object. $parent does not seem to point to the object that is expanded on the most outer select.
Edit 2
I'm Playing with $parent in every way I can think of. I don't see how you can use it in this case. Again - the problem I'm trying to solve is how to pass the sum(value) to the outer result set. I don't see a way of using LET for it when doing a GROUP BY, and I also don't see a way of using LET when the outer most select is doing an expand (since you can't do other projections together with expand).
Also, the results of using $current do not seem to be what is expected. For example, the following query:
select expand($v) from
(select from
(select expand(inE("Liked", "Commented")) from Profile where #rid=#11:0)
let $v = $current
)
Returns this:
{
"result" : [{
"#type" : "d",
"#rid" : "#14:4",
"#version" : 2,
"#class" : "Commented",
"value" : 1,
"out" : "#11:165",
"in" : "#11:0"
}, {
"#type" : "d",
"#rid" : "#14:4",
"#version" : 2,
"#class" : "Commented",
"value" : 1,
"out" : "#11:165",
"in" : "#11:0"
}, {
"#type" : "d",
"#rid" : "#14:4",
"#version" : 2,
"#class" : "Commented",
"value" : 1,
"out" : "#11:165",
"in" : "#11:0"
}
]
}
The same node over and over again, instead of all the edges, which is what I would expect.

Answer 1

I see you're using an old version of OrientDB. With more recent versions you can simplify it by. Example: original query:
select * from (
traverse out from (
select out, sum(value) as value from (
traverse * from (
select from Profile where username="B"
) while $depth < 3
) where #class="Liked" or #class="Commented" group by out order by value desc
) while $depth < 2
) where #class="Profile" )
You could skip some step by using out()/in()/both() passing the Edge's labels/class like:
select expand( out(["Liked","Commented]) ) from Profile where username="B"
However to pass the value you can use variables with LET clause. Example:
select from XXX let $parent.a = value
In this way you set the variable "a" into the upper level context, but you could do also:
select from XXX let $parent.$parent.a = value
To set it 2 levels up.

Answer 2

I haven't tried this with a group by yet, but you should be able to group the result using a sub query. This works for me, where prop1, prop2, prop3, etc are properties of the vertices coming out of the edge (the columns resulting from select out() Profile where username="B")
select outV().prop1, outV().prop2, outV().prop3, value from (
select expand(inE("Liked", "Commented")) from Profile
where username="B"
) order by value desc