How can I do conditional sort on Gremlin/Neptune

Question

I am trying to build a query that will return a Vertex both edges, and sort them conditionally by value of a different property according to whether the original Vertex is the out Vertex or in Vertex in the given edge, I have two properties that will comply with this sort ("origin_pinned" & "target_pinned"), if an edge in Vertex is the original vertex I want to use "origin_pinned" value if its the out vertex then I want to use "target_pinned" value

This must be one query

I tried to run the following query but does not seem to have effect:

g.V('id123').bothE().order().by(values(choose(inV().is(V('id123')), 
constant('origin_pinned'), constant('target_pinned'))), desc)

Answer 1

The values step will not work the way you are trying to use it. You did not include any sample data in the question, but using the air-routes data set, the query can most likely be simplified as shown below:

gremlin> g.V(44).as('a').
......1>   bothE().
......2>   order().
......3>     by(coalesce(
......4>         where(inV().as('a')).constant('origin_pinned'),
......5>         constant('target_pinned')))

==>e[57948][3742-contains->44]
==>e[54446][3728-contains->44]
==>e[4198][13-route->44]
==>e[4776][31-route->44]
==>e[4427][20-route->44]
==>e[4015][8-route->44]
==>e[5061][44-route->8]
==>e[5062][44-route->13]
==>e[5063][44-route->20]
==>e[5064][44-route->31] 

and to prove the reverse also works

gremlin> g.V(44).as('a').
......1>   bothE().
......2>   order().
......3>     by(coalesce(
......4>         where(outV().as('a')).constant('origin_pinned'),
......5>         constant('target_pinned')))

==>e[5061][44-route->8]
==>e[5062][44-route->13]
==>e[5063][44-route->20]
==>e[5064][44-route->31]
==>e[57948][3742-contains->44]
==>e[54446][3728-contains->44]
==>e[4198][13-route->44]
==>e[4776][31-route->44]
==>e[4427][20-route->44]
==>e[4015][8-route->44]     

To check things are working as expected, we can do:

gremlin> g.V(44).as('a').
......1>   bothE().as('e').
......2>   coalesce(
......3>     where(inV().as('a')).constant('origin_pinned'),
......4>     constant('target_pinned')).as('p').
......5>     order().
......6>   select('e','p')

==>[e:e[57948][3742-contains->44],p:origin_pinned]
==>[e:e[54446][3728-contains->44],p:origin_pinned]
==>[e:e[4198][13-route->44],p:origin_pinned]
==>[e:e[4776][31-route->44],p:origin_pinned]
==>[e:e[4427][20-route->44],p:origin_pinned]
==>[e:e[4015][8-route->44],p:origin_pinned]
==>[e:e[5061][44-route->8],p:target_pinned]
==>[e:e[5062][44-route->13],p:target_pinned]
==>[e:e[5063][44-route->20],p:target_pinned]
==>[e:e[5064][44-route->31],p:target_pinned]