Cypher с Neo4j: заказывать предметы в сборе и не иметь пустых предметов

Question

Я пытаюсь написать запрос на шифрование, в котором все время записывается для куба человека.Запрос работает нормально, но я вижу, что если в результатах нет времени (Time) - [: RECORDED_ON] - (Cube), я получаю 1 запись в наборе с обоими значениями null.Кроме того, я хотел бы заказать дату в коллекции времен DESC

Вот мой шифр:

MATCH(a:App{name:'AllAboutCubes'})<-[:MEMBER_OF]-(p:Cuber) WHERE id(p) = 1234
MATCH(p)<-[:BELONGS_TO {is_active:1}]-(c:Cube)
OPTIONAL MATCH (c)-[:TYPE]->(ct:CubeType)
OPTIONAL MATCH (c)<-[:RECORDED_ON]-(t:Time)-[:RECORDED]-(p) 
WITH c,ct,COLLECT({time:t.time,date:t.date}) as times
RETURN c.name as name, c.manufacturer as manufacturer, ct.type as type, id(c) as cube_id, times as times
ORDER BY manufacturer ASC

Но я вернусь:

"name"  "manufacturer"  "type"  "cube_id"   "times"
"Weipo" "MoYu"  "2x2"   7452    [{"time":null,"date":null}]
"GTS3M" "MoYu"  "3x3"   7453    [{"time":null,"date":null}]
"MoYu Skewb"    "MoYu"  "Skewb" 7458    [{"time":"12.435","date":1553880809832}]
"WuQue" "QiYi MoFangGe" "4x4"   7459    [{"time":null,"date":null}]
"Valk 3"    "QiYi MoFangGe" "3x3"   7454    [{"time":null,"date":null}]
"Mini Rose Valk 3"  "QiYi MoFangGe" "3x3"   7456    [{"time":null,"date":null}]
"Valk 2"    "QiYi MoFangGe" "2x2"   7450    [{"time":null,"date":null}]
"ChuWen M"  "Supernova" "2x2"   7484    [{"time":null,"date":null}]
"Wingy" "X-Man Designs" "Skewb" 7457    [{"time":"12.255","date":1553881012244},{"time":"13.49","date":1553212800000}]
"Bell"  "X-Man Designs" "Pyraminx"  7478    [{"time":"9.234","date":1553817600000}]
"Ruipo" "YJ"    "2x2"   7451    [{"time":null,"date":null}]
"Little Magic"  "YuXin" "3x3"   7455    [{"time":null,"date":null}]

, к которомуЯ не хочу, чтобы [{"time": null, "date": null}]

Есть идеи?Спасибо и дайте мне знать!

Answer 1

Это должно отсортировать даты в порядке убывания и вернуть [] для times, когда нет дат:

MATCH (a:App{name:'AllAboutCubes'})<-[:MEMBER_OF]-(p:Cuber) WHERE id(p) = 1234
MATCH (p)<-[:BELONGS_TO {is_active:1}]-(c:Cube)
OPTIONAL MATCH (c)<-[:RECORDED_ON]-(t:Time)-[:RECORDED]-(p)
WITH c, t ORDER BY t.date DESC
OPTIONAL MATCH (c)-[:TYPE]->(ct:CubeType)
WITH c, ct, CASE WHEN t IS NULL THEN [] ELSE COLLECT({time:t.time,date:t.date}) END as times
RETURN c.name as name, c.manufacturer as manufacturer, ct.type as type, id(c) as cube_id, times
ORDER BY manufacturer