Question

我正在使用LOAD CSV导入节点和关系，但其中一列是＆＃34; country_id＆＃34;我用来创建与另一个的关系在输入数据集中有时不是NULL，只有当列具有值时才会如何进行条件MERGE。我试过＆＃34; CASE＆＃34;但它不适用于＆＃34; IS NOT NULL＆＃34;。谢谢。路易斯奥斯卡
以下是我的代码，目前为country_id删除NULL＆＃39; s：

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

如果coalesce为空，则可以使用密码country_id函数设置默认值：MERGE (c:Country {code:coalesce(row.country_id, 'NULL')})

在您的LOAD CSV完成后，您可以进行清理查询以删除您的默认国家/地区：DETACH DELETE (c:Country code:'NULL'});

如果在使用LOAD CSV加载数据时列具有值，则如何条件MERGE

1 个答案: