Why these differences in Query?

General Graph Academy
1

Hi,

in "intermediate cypher" I created two queries:

MATCH (m:Movie)
WHERE m.year = 2015
RETURN m.title,
[(dir:Person)-[:DIRECTED]->(m) | dir.name] AS directors
-> Returns 180 People

MATCH (m:Movie) <-[:DIRECTED] - (p:Person)
WHERE m.year = 2015
RETURN m.title, collect(p.name) AS directors
-> Returns 178 People

Why does the first Query include empty lists (two movies with as directors while the second does not?

Is there a command for whether a property has more than one entry?

Bye

Michael

2

List comprehension will return an empty list when no matches are found. Matching followed by collecting will not return an empty list when there is not a match and you are grouping.

1 Like
3

What Gary said :+1:.

collect() considerations - Any null values are ignored and will not be added to the list.

1 Like