How to query symmetric graph and return non duplicate rows

Hi,

Run into the issue where Cypher returns two rows per my query per each path.

Here are Cypher statements to demonstrate my issue:

//Create nodes and relationships:
CREATE (:Person { Name: "Max"})
CREATE (:Person { Name: "Sam"})
CREATE (:Person { Name: "Nil"})

MATCH (a:Person) where a.Name="Max"
MATCH (b:Person) where b.Name="Sam"
MATCH (c:Person) where c.Name="Nil"
CREATE (a)-[:KNOWS]->(b)
CREATE (a)-[:KNOWS]->(c)

//Graph now looks like this:
(Sam)<-[KNOWS]-(Max)-[KNOWS]->(Nil)

//Run query:
MATCH (p1:Person)<--(:Person)-->(p2:Person)
RETURN p1.Name, p2.Name

//Results I get
p1.Name p2.Name
"Nil" "Sam"
"Sam" "Nil"

While desired results would be:
p1.Name p2.Name
"Nil" "Sam"

or
p1.Name p2.Name
"Sam" "Nil"

How do I instruct Cypher to traverse this symmetric path only once and return one row in results instead of two.

Add a condition? WHERE p1 <> p2

You could add a where clause to compare the two nodes and only return one when a property is higher than the other - either by property, internal id or just simply:

WHERE p1 > p2

Tried this:
MATCH (p1:Person)<--(:Person)-->(p2:Person)
WHERE p1 <> p2
RETURN p1.Name, p2.Name

Returns:

p1.Name p2.Name
"Nil" "Sam"
"Sam" "Nil"

That one works, tried:
MATCH (p1:Person)<--(:Person)-->(p2:Person)
WHERE id(p1) > id(p2)
RETURN p1.Name, p2.Name

Returns:

p1.Name p2.Name
"Nil" "Sam"

Are there any more "natural" way to get desired results similar to what "distinct" clause does but on a path level?

At the same time, running this query:
MATCH (p1:Person)<--(:Person)-->(p2:Person)
WHERE p1 > p2
RETURN p1.Name, p2.Name

Returns Error:
Type mismatch: expected Float, Integer, Point, String, Date, Time, LocalTime, LocalDateTime or DateTime but was Node (line 2, column 7 (offset: 50))
"WHERE p1 > p2"