CALL - GQL Docs

CALL statement in GQL invokes a Procedure. It runs a contained query for the current outer result.

For each node find the number of incoming edges

Suppose we are interested in the number of highways flowing into each of the Highway: We can use the CALL statement to invoke and inline procedure as follows:

MATCH nodes = (b)
CALL {
  MATCH path = (a)-[e1:flows_to]->(b)
  return path
    , count(distinct e1) as incoming_nodes_count
    , COLLECT_LIST(distinct a.name) as incoming_nodes
}
return table(b.name, incoming_nodes_count, incoming_nodes)
order by incoming_nodes_count desc;

For each node list paths to all other nodes

We are interested in getting all paths from each to all other nodes:

MATCH nodes = (a)
CALL {
  MATCH path = (a)-[edges:flows_to]->{0,}(b)
  return reduce(path = a._id, edge in edges | path || '->' || edge._to) as route
  , b
  
}
return table(a.name as starting, b.name as ending, route)

Movie recommendations based on what the 1 degree connection and 2nd degree connection have watched

Recommend movies based on what account 1st and 2nd degree connection have watched:

MATCH friends = ALL  (account_a)-[:friends]->{0,2}(account_b)
CALL {
  MATCH path = (account_a)-[:watched]->(movie_a)
    , (account_b)-[:watched]->(movie_b)
  FILTER account_a <> account_b and movie_a <> movie_b
  return path
    , COLLECT_LIST(distinct movie_a.title) as recommended_movies
}
FILTER account_a <> account_b
return table(account_a.name, account_b.name, recommended_movies);