Using label(n) in unwind gives me no result

[rob2]

HI
I can't get the following commands to work together. individually they do work

1st command

MATCH (a) WITH LABELS(a) AS temp UNWIND temp AS LABELLIST return DISTINCT LABELLIST;

gives me

LABELLIST
	"node"
	"status"
	"process"
	"org"
	"account"
	"mail"
	"person"
	"topic"
	"course"
	"exam"
	"exam_certificate"

2nd command

MATCH (n:org)-[:managed_by_process]->(m) return DISTINCT m.guid;

is working and gives me "a83265b2-3fbc-48bd-855e-504436ffc736"

togehether gives me nothing - the label shall be from the list ....

MATCH (a) WITH DISTINCT LABELS(a) AS temp UNWIND temp AS LABELLIST
MATCH (n:LABELLIST)-[:managed_by_process]->(m) return m;

Thanks for help rob

also NOT working

MATCH (a) WITH DISTINCT LABELS(a) AS temp UNWIND temp AS LABELLIST
WITH LABELLIST
MATCH (n:LABELLIST)-[:managed_by_process]->(m) return m;

[dana_canzano]

im interested to know what the end goal is. for example

MATCH (a) WITH DISTINCT LABELS(a) AS temp UNWIND temp AS LABELLIST
WITH LABELLIST
MATCH (n:LABELLIST)-[:managed_by_process]->(m) return m;

appears to be
line1: traverse all nodes and collect all distinct labels for all nodes and then unwind from this set each label
line3: for each label find all nodes for this label see if it has a :managed_by_process relationship pointing to any other node and then return this any other node.

Why not simply

MATCH (n)-[:managed_by_process]->(m) return m;

which says, traverse all nodes see it it has a relationship named :managed_by_process pointing to some other node and then return that other node?

[rob2]

hi Dana

Thanks your answere helped me a lot - sometimes you can't see the forest for the trees

my soltion is now

MATCH (n)-[:managed_by_process]->(m) return labels(n), m.guid

im interested to know what the end goal is.

the result tells me that all nodes with the label e.g. "mail" have the managing process with the GUID "0d821309-b677-49d6-b7b4-7083e8fd5a86"

at the moment the result is not distinct (over all cells in a row)
I get

["mail"]            "0d821309-b677-49d6-b7b4-7083e8fd5a86"
["mail"]            "0d821309-b677-49d6-b7b4-7083e8fd5a86"
["exam_certificate"]"ff698ee5-76e4-4903-8f97-cb1d4949a8b1"
["exam_certificate"]"ff698ee5-76e4-4903-8f97-cb1d4949a8b1"
["exam_certificate"]"ff698ee5-76e4-4903-8f97-cb1d4949a8b1"
["exam"]            "15949010-a42a-44b4-9d22-aa17f68afb1b"
["exam"]            "15949010-a42a-44b4-9d22-aa17f68afb1b

perefect would be

["mail"]            "0d821309-b677-49d6-b7b4-7083e8fd5a86"
["exam_certificate"]"ff698ee5-76e4-4903-8f97-cb1d4949a8b1"
["exam"]            "15949010-a42a-44b4-9d22-aa17f68afb1b"

I tried

MATCH (n)-[:managed_by_process]->(m) return distinct (labels(n), m.guid)

which is not working , so my workarround is

MATCH (n)-[:managed_by_process]->(m) return distinct (labels(n)+m.guid)

[dana_canzano]

just a note that your queries though valid are performing a allNodesScan. so if you have 100 million nodes, then each time you run the query then we will traverse all 100 million nodes.

Now if you changed for example

MATCH (n)-[:managed_by_process]->(m) return distinct (labels(n)+m.guid)

to

MATCH (n:mail)-[:managed_by_process]->(m) return distinct (labels(n)+m.guid)

and of the 100 million total nodes in the graph, if only 8 million had a label of mail then we would only travese 8 million nodes

[ameyasoft · Accepted solution]

rob2:

MATCH (n)-[:managed_by_process]->(m) return distinct (labels(n), m.guid)

Try this:
MATCH (n)-[:managed_by_process]->(m) return distinct labels(n) as lbl, m.guid

[rob2]

my final solution is this (incuding all keys per label)

MATCH (n)-[:managed_by_process]->(m) return distinct labels(n) as lbl, COLLECT(distinct (apoc.coll.sort(keys(n)))) as kys, m.guid

with the help of this answer to my "old" question Keys(n) sorting problems with DISTINCT

THANKS a lot - greate Community here !