Wie bedingte MERGE nur, wenn die Spalte Wert hat, wenn LOAD CSV verwendet, um Daten zu laden

Question

Ich verwende LOAD CSV, um Knoten und Relationen zu importieren, aber eine der Spalten die "country_id", die ich verwende, um die Beziehung mit anderen nicht zu erstellen ist im Eingangsdatensatz NULL, wie macht man bedingte MERGE nur dann, wenn die Spalte einen Wert hat. Ich habe das "CASE" versucht, aber es funktioniert nicht mit "IS NOT NULL". Danke. Luis Oscar
Das folgende ist mein Code zur Zeit für country_id discarting NULL ist:

USING PERIODIC COMMIT 20 
LOAD CSV WITH HEADERS FROM 'file:///physical_location.csv' as row 
WITH 
toInt(row.physical_location_id) as physical_location_id, 
CASE row.country_id WHEN IS NOT NULL THEN MERGE (c:Country {code:country_id}) END, 
toFloat(row.latitude)  as latitude, 
toFloat(row.longitude)  as longitude, 
row.addressline1   as addressline1, 
row.addressline2   as addressline2, 
row.cityname    as cityname, 
row.postalcode    as postalcode, 
row.telephone    as telephone, 
row.airport     as airport, 
row.railway     as railway, 
row.ferryport    as ferryport, 
row.iata_airport_code  as iata_airport_code, 
row.iata_city_code   as iata_city_code, 
row.timezone    as timezone, 
row.pickup_only    as pickup_only, 
row.return_only    as return_only, 
row.outofhours_return  as outofhours_return, 
row.dropbox     as dropbox, 
row.delivery_collection  as delivery_collection, 
row.pl_email    as pl_email 
//where country_id IS NOT NULL 
MERGE (pl:PhysicalLocation {physical_location_id:physical_location_id}) 
ON MATCH SET 
    pl.addressline1   = addressline1, 
    pl.addressline2   = addressline2, 
    pl.cityname    = cityname, 
    pl.postalcode   = postalcode, 
    pl.telephone    = telephone, 
    pl.airport    = airport, 
    pl.railway    = railway, 
    pl.ferryport    = ferryport, 
    pl.iata_airport_code  = iata_airport_code, 
    pl.iata_city_code  = iata_city_code, 
    pl.timezone    = timezone, 
    pl.pickup_only   = pickup_only, 
    pl.return_only   = return_only, 
    pl.outofhours_return  = outofhours_return, 
    pl.dropbox    = dropbox, 
    pl.delivery_collection = delivery_collection, 
    pl.pl_email    = pl_email 
//MERGE (pl)-[r:IN_COUNTRY]->(c) 
RETURN count(pl) 

Answer 1

Sie können Chiffre coalesce Funktion verwenden, um einen Standardwert zu haben, wenn Ihr country_id ist null: MERGE (c:Country {code:coalesce(row.country_id, 'NULL')})

Nach, Wenn Ihre CSV-Datei geladen ist, können Sie eine Bereinigungsabfrage machen, um Ihr Standardland zu entfernen mit: DETACH DELETE (c:Country code:'NULL'});