Is it possible to return count() from Cypher pattern comprehension ?
The following query doesn’t work:
[ (:Vacancy)<-[rpp:POTENTIAL_PROFILE]-(childD) | count(rpp) ] AS potentialJobablesCount
with the following error:
Aggregation column contains implicit grouping expressions. For example, in 'RETURN n.a, n.a + n.b + count(*)' the aggregation expression 'n.a + n.b + count(*)' includes the implicit grouping key 'n.b'. It may be possible to rewrite the query by extracting these grouping/aggregation expressions into a preceding WITH clause. Illegal expression(s): rpp
>Solution :
Aggregation functions like COUNT can only be used in WITH and RETURN clauses.
But starting with neo4j 5.0 you can use the new COUNT subquery. For example:
MATCH (childD:ChildD {id:123})
RETURN COUNT { (:Vacancy)<-[:POTENTIAL_PROFILE]-(childD) } AS potentialJobablesCount