6.5 Variable-Length Paths with PGQL
Variable-length path patterns have a quantifier like * to match a variable number of vertices and edges. Using a PATH macro, you can specify a named path pattern at the start of a query that can be embedded into the MATCH clause any number of times, by referencing its name. The following example finds all of the common ancestors of Mario and Luigi.
PATH has_parent AS () -[:has_father|has_mother]-> ()
SELECT ancestor.name
FROM MATCH (p1:Person) -/:has_parent*/-> (ancestor:Person)
, MATCH (p2:Person) -/:has_parent*/-> (ancestor)
WHERE
p1.name = 'Mario' AND
p2.name = 'Luigi'
The preceding path specification also shows the use of anonymous constraints, because there is no need to define names for intermediate edges or nodes that will not be used in additional constraints or query results. Anonymous elements can have constraints, such as [:has_father|has_mother]
-- the edge does not get a variable name (because it will not be referenced elsewhere), but it is constrained.
For more examples of variable-length path pattern matching, see the Variable-Length Paths section in the PGQL specification.
Parent topic: Property Graph Query Language (PGQL)