Using YIELD after CALL

[maarriaa]

Hi!
I'm trying to use CALL apoc.do.when() but I can't figure out how to use YIELD properly.
Here is my query:

LOAD CSV WITH HEADERS FROM "file:///example_drugs.csv" as drugs 

MERGE (d:Drug {drugbankId: drugs.drugbankId})
SET d.name= drugs.name
SET d.description= drugs.description
SET d.casNumber= drugs.casNumber
SET d.unii= drugs.unii
SET d.state= drugs.state

WITH drugs.productName as productName, d
CALL apoc.do.when(productName IS NOT NULL, 
"MERGE (p:Product{name: productName}) MERGE (d)-[r:HAS_PRODUCT]-(p)", YIELD ???) 
return p

I tried to put YIELD in various places, but every time I get a error. Could someone help me with writing this query properly?

[terryfranklin82]

apoc.do.when requires both an if and else statement, it looks like you only have the first part.

Also yield should appear outside of the function, e.g. the function yields a value:

CALL apoc.do.when(....) YIELD...