Question

有关注图

CREATE (s1:SOME {id:'s1'} )  
CREATE (s2:SOME {id:'s2'} )
CREATE (a11:ANOTHER {id:'a11', tags:["tag1", "tag2"] } )
CREATE (a12:ANOTHER {id:'a12', tags:["tag2", "tag3"] } )

CREATE (a21:ANOTHER {id:'a21', tags:["tag3", "tag4"] } )
CREATE (a22:ANOTHER {id:'a22', tags:["tag4", "tag5"] } )

CREATE (s1)-[:CONTAINS ]->(a11),
(s1)-[:CONTAINS ]->(a12),
(s2)-[:CONTAINS ]->(a21),
(s2)-[:CONTAINS ]->(a22)

并使用以下查询填充记录：

match (s:SOME)
    with s 
    OPTIONAL MATCH  (a:ANOTHER)-[r:CONTAINS]-(s)
    WITH s, COLLECT(DISTINCT a) AS aa

return s.id, aa

现在我想对ANOTHER.tags字段添加一些限制：

match (s:SOME)
    with s 
    OPTIONAL MATCH  (a:ANOTHER)-[r:CONTAINS]-(s)
    where 'tag2' in a.tags
    WITH s, COLLECT(DISTINCT a) AS aa

return s.id, aa

结果：

╒══════╤══════════════════════════════════════════════════════════════════════╕
│"s.id"│"aa"                                                                  │
╞══════╪══════════════════════════════════════════════════════════════════════╡
│"s2"  │[]                                                                    │
├──────┼──────────────────────────────────────────────────────────────────────┤
│"s1"  │[{"id":"a11","tags":["tag1","tag2"]},{"id":"a12","tags":["tag2","tag3"│
│      │]}]                                                                   │
└──────┴──────────────────────────────────────────────────────────────────────┘

但是我想完全跳过s2记录，因为它不包含必需的标记

另一件事-如果我要检查多个标签怎么办？像[“ tag1”，“ tag2”]（在这种情况下应该用空数据响应）我可以使用类似交集的东西吗？

Answer 1

您只需要从OPTIONAL MATCH切换到MATCH，它应该跳过空值。

我们还可以仅使用一个MATCH而不是两个来缩短查询：

match (s:SOME)<-[r:CONTAINS]-(s)
where 'tag2' in a.tags
WITH s, COLLECT(DISTINCT a) AS aa

return s.id, aa

查询嵌套对象

1 个答案: