Execute multiple query based on multiple condition in cypher / apoc

Question

In cypher or APOC, Is there a way to execute multiple query based on multiple condition. I need something similar this APOC

CALL apoc.do.case([condition, query, condition, query, …], elseQuery:'', 
params:{}) yield value

But here as soon as we met 1st true condition it skip all further condition and query. I want to execute all those query where my condition is true.

In simple word , I am looking for something similar to java case statement (without break; between case)

Update

I ran following query to use multiple apoc.do.when but it seems only my second apoc.do.when is not executing:

CREATE (y:EVENT { _id: 1, localComponentID:'l1', externalComponentID:'e1'}) with y 

call apoc.do.when(exists(y.localComponentID),"MATCH(e:EVENT) where 
e.localComponentID = lcl and e._id <> y._id with  y,e limit 1 create (y)-
[r:LOCAL_LINK]->(e)",'',{y:y,lcl:y.localComponentID}) YIELD value WITH value AS ignored, y

call apoc.do.when(exists(y.externalComponentID),"MATCH(e:EVENT) where 
e.externalComponentID = ext and e._id <> y._id with  y,e limit 1 create (y)-
[r:EXTERNAL_LINK]->(e)",'',{y:y, ext:y.externalComponentID}) YIELD value 
WITH value AS ignored return ignored

If I run above query two time with _id = 1 in first run and _id=2 in second run, I expect two EVENT connected with LOCAL_LINK and EXTERNAL_LINK. But I am only getting LOCAL_LINK between them not the EXTERNAL_LINK. I am not sure what I am doing wrong.

Note : I am using limit 1 because In case of multiple match I just want to create LINK with one node.

Update 2

Got it working , In my sample query I was that not returning y from first apoc.do.when

Here is the updated query which works:

CREATE (y:EVENT { _id: 1, localComponentID:'l1', externalComponentID:'e1'}) with y 

call apoc.do.when(exists(y.localComponentID),"MATCH(e:EVENT) where 
e.localComponentID = lcl and e._id <> y._id with  y,e limit 1 
create (y)-[r:LOCAL_LINK]->(e) RETURN y",'',
{y:y,lcl:y.localComponentID}) YIELD value WITH value AS ignored, y

call apoc.do.when(exists(y.externalComponentID),"MATCH(e:EVENT) where 
e.externalComponentID = ext and e._id <> y._id with  y,e limit 1 
create (y)-[r:EXTERNAL_LINK]->(e)",'',{y:y, ext:y.externalComponentID}) 
YIELD value 
WITH value AS ignored return ignored

Sounds useful, however there are some complications. We can return results easily from this procedure because only one query will be executed as a result. To support multiple queries executing, we'd likely have to restrict all queries to write-only. — InverseFalcon
Yes, I agree. And in my particular case all queries are write only query. — Shishal
That could work. Can you add an issue with this request to the APOC GitHub? — InverseFalcon
created issue on apoc github github.com/neo4j-contrib/neo4j-apoc-procedures/issues/742 — Shishal

cybersam cybersam · Accepted Answer · 2018-02-16T00:23:07

You can just call the APOC function apoc.do.when for each condition/query pair (with an empty string as the else argument).

For example:

CALL apoc.do.when(<condition1>, <query1>, '', {}) YIELD value
WITH value AS ignored
CALL apoc.do.when(<condition2>, <query2>, '', {}) YIELD value
WITH value AS ignored
.
.
.

Since your comments indicate your queries are all write-only, the above example assigns the return values to an ignored variable (that you can ignore).

Execute multiple query based on multiple condition in cypher / apoc

1 Answers