场景：查询两点路径中通过某一顶点的路径
语句：
FIND ALL PATH FROM "player100" TO "player101" OVER * BIDIRECT YIELD path as p |
YIELD $-.p WHERE "player104" IN [n in nodes($-.p)| id(n)]
适用版本： v2.6, v3.x
注释：这里重点在于列表展开的表达
出处：https://gist.github.com/wey-gu/f41e8a5651d95506b37bee6a8b5a1b8c
场景：查询出很多刚导入的图给 studio/explorer 进行可视化，支持 3.0 的无索引场景
语句：
MATCH (n) WITH n LIMIT 1000
OPTIONAL MATCH p=(n)--()
RETURN p, n
或者
MATCH (n) WITH n LIMIT 1000
OPTIONAL MATCH (n)-[e]-(m)
RETURN n,e,m
适用版本： v3.x
注释：这里重点在于在 3.0~3.4 中，不允许无索引的数据全扫描的情况下，利用 LIMIT 去扫数据
出处：https://gist.github.com/wey-gu/f41e8a5651d95506b37bee6a8b5a1b8c
场景：如果想要通过描述多跳的边的过滤条件，比如-[e:follow*2]->，这时候变量 e 不再是单条边时候的数据类型了，而是一列边组成的列表，例如： 以下语句可以运行但是没有返回数据，因为e是一个列表，没有.degree的属性。
错误的表达：
这里 e 没有
.degree，所以条件一定不满足
MATCH p=(v:player{name:"Tim Duncan"})-[e:follow*2]->(v2) \
WHERE e.degree > 1 \
RETURN DISTINCT v2 AS Friends;
语句：
-- 限制所有 follow 边
MATCH p=(v:player{name:"Tim Duncan"})-[e:follow*2]->(v2) \
WHERE ALL(e_ in e WHERE e_.degree > 0) \
RETURN DISTINCT v2 AS Friends;
或者放在花括号里
MATCH (n:player)-[e:follow*3{degree:95}]-(v)
RETURN n
-- 限制第一个 follow
MATCH p=(v:player{name:"Tim Duncan"})-[e:follow*2]->(v2) \
WHERE e[0].degree > 98 \
RETURN DISTINCT v2 AS Friends;
适用版本： v2, v3
注释：边变量可变长度时候是一个 list
出处：https://gist.github.com/wey-gu/f41e8a5651d95506b37bee6a8b5a1b8c
由于 NebulaGraph 的每个版本的子句使用会存在出入，以下语句不代表适用于所有的 NebulaGraph 发行版；此外，由于个别语句对特定场景生效，不代表它具有通用性！
match (v:player)-[e*1…]->(v2) where id(v)==“player100” return count(distinct v2)match (v:player)-[e*1..]->(v2:player) where id(v)=="player100" return count(distinct v2)match (e)–(d)–(a)–(b)–(c) where (d)–(b) return bmatch p=(a)-[e1]-(b)-[e2]-(c) optional match (c)-[e3]-(d) return p;(((lookup on like yield like._src as srcId |go from $-.srcId over like yield id($$) as vid) minus (lookup on like yield like._src as srcId | go from $-.srcId over like yield id($$) as dstId | fetch prop on * $-.dstId yield id(vertex) as vid)) | go from $-.vid over * bidirect yield distinct id($^) as srcId, id($$) as dstId) | delete edge like $-.srcId->$-.dstId 再执行 (((lookup on like yield like._src as srcId |go from $-.srcId over like yield id($$) as vid) minus (lookup on like yield like._src as srcId | go from $-.srcId over like yield id($$) as dstId | fetch prop on * $-.dstId yield id(vertex) as vid)) | go from $-.vid over * bidirect yield distinct id($^) as srcId, id($$) as dstId) | delete edge like $-.dstId->$-.srcIdget subgraph 2 steps from "Tim Duncan" both serve yield vertices as a | unwind $-.a as t | yield $-.t where "player" in tags($-.t)MATCH (v:A) RETURN size((v)-->()) AS out_degree1, size((v)-->()-->()) AS out_degree2MATCH (v:A) WHERE size((v)-->()-->()) > size((v)-->()) RETURN vmatch (v:player{name:“Tim Duncan”})-[e*1…2]->(v2) unwind e as edgelist return edgelist// 1
MATCH(v)-[e:person_knows_person*1..3]-(v2) WHERE v.person.firstName == "firstName"
// 2
OPTIONAL MATCH (v2)-[e2: person_isLocatedIn_place]-(v3)
// 3
OPTIONAL MATCH (v2)-[e3: person_studyAt_organisation]-(v4)
// 4
OPTIONAL MATCH (v2)-[e3: person_workAt_organisation]-(v5)
// 查找国家
...
WITH v2 as personName, v3 as workingPlace, v4 as college, v5 as company
RETURN personName, workingPlace, college, company, country
MATCH p=(v)-[e:follow]-(v2) WHERE id(v) == "player10" and rank(e) == 1 RETURN pLIMIT 100
# LOOKUP
lookup on edge_name yield edge as e | yield count(*)
# MATCH
match (m) - [e:edge_name] - (n) return count(e)
# SHOW STATS
看文档：https://docs.nebula-graph.com.cn/3.4.1/3.ngql-guide/7.general-query-statements/6.show/14.show-stats/
match (v:tagName) where id(v)==‘123A123’ return v.tagName.prop1
Lookup on `in_user` where in_user.user_type == 2 yield src(edge) as src, dst(edge) as dst | delete edge `in_user` $-.src->$-.dst
lookup on player yield id(vertex) as vid
minus
(lookup on player yield id(vertex) as vid | go 1 step from $-.vid over * bidirect yield distinct id($^) as vid)
)
| delete vertex $-.vid
get subgraph 5 step from pod in have,belong yield vertices as nodes, edges as relationshiops
union all
get subgraph 5 step from pod out have,belong yield vertices as nodes, edges as relationshiops
MATCH (a)-[e1]->(b)-[e2]->(c)
WITH e1.cost+e2.cost as cost, c ORDER BY cost
RETURN c
MATCH (a)-[b]->(c) where id(a)="*****"
WITH labels(c) AS ctype, collect(distinct c)[0..10] AS c_with_same_type
UNWIND c_with_same_type AS cc
OPTIONAL MATCH (cc)-[d]->(e)
RETURN cc, d, e
LOOKUP ON ip YIELD id(vertex) as id
| GO FROM $-.id over activeIn REVERSELY
WHERE head(labels($)) == 'equipment'
YIELD id($) as dst, id($^) as src
| GO FROM $-.dst over login REVERSELY
WHERE head(labels($)) == 'account'
YIELD id($) as dst, id($^) as src
|GROUP BY $-.src YIELD $-.src as src,count($-.src) as degree
| YIELD $-.src as src where $-.degree > $p0
| GO FROM $-.src over login REVERSELY
YIELD properties($).accountUuid as accountUuid
go from "dst ip" over url_ip REVERSELY yield id($) as url
| go from $-.url over * yield type(edge) as et, edge as e
match (v1:player)-[e:serve]->(v2:team)
with max(rank(e)) as max_rank
match (v3:player)-[e2:serve]->(v4:team)
where rank(e2) == max_rank
return count(e2);
lookup on A yield id(vertex) as vid | delete vertex $-.vid
lookup on E yield E._src as src,E._dst as dst|delete edge E $-.src->$-.dst
MATCH (v:player)-[e:follow]-(v2)
WHERE id(v) == 'player100' AND e.degree > 85
RETURN v2.player.name, e.degree;
#大于等于 2
MATCH (:房间)<-[:入住]-(v:人)-[:入住]->(:房间)
RETURN distinct v
#大于 2
MATCH (v:人)-[:入住]->(:房间)
where size((v)-[:入住]->())>2
RETURN distinct v
MATCH p=(v)-[*1..10]-(m)
where id(v)=="host001" and all( midNode in [n in nodes(p) where id(n)<>id(v) | n] where "frontPort" not in tags(midNode))
RETURN p
MATCH (v)-[e:follow]->(n) where id(v) in ["player101"]
WITH id(v) AS vid1, id(n) AS vid2 collect(e) AS edge1 where size(edge1)==1
RETURN edge1
MATCH p=(v:tag)-[:blood*1..10]->(v)
RETURN p
((lookup on table | yield $-.VertexID as id)
MINUS
(lookup on table | yield $-.VertexID as id | go from $-.id over * BIDIRECT yield $-.id as id))
| delete $-.id
MATCH (v:table)
WHERE not (v)--()
RETURN id(v)
match (v) with properties(v) as props, keys(properties(v)) as kk, v limit 10000 where [i in kk where props[i] == “Tony Parker”] return v
match ()-[e]->() with e, properties(e) as props, keys(properties(e)) as kk limit 10000 where [i in kk where props[i] == 90] return e
fetch prop on * "vertex_id" yield properties(vertex);
MATCH p=(v1:company)-[*1..10]->(v2:company)-[:SHList]->(v3:person)
WHERE id(v1)=="company1"
RETURN v3.person.name, p
#GO
GET SUBGRAPH 10 steps FROM "Tim Duncan" IN EdgeType YIELD VERTICES AS nodes | yield $-.nodes[6]
#MATCH
MATCH (v)<-[:EdgeType*1..10]-(n)
WHERE id(v)=="vid" AND NOT (n)<-[:EdgeType]-()
RETURN n
MATCH (n:player)
RETURN n.player.name AS name
UNION
MATCH (n:team)
RETURN n.team.name AS name
nebula> GO 3 STEPS FROM "player100" \
OVER * \
YIELD properties($).name AS NAME, properties($).age AS Age \
LIMIT [3,3,3];
推荐一个帖子
里面讲述了一些 nGQL 书写的 tips。
GO 3 STEPS FROM "ADDRESS_1015" OVER related YIELD
case when $^.Staff.STAFF_NAME IS NOT EMPTY and $^.Staff.STAFF_ROLE == "派送人员" then related._src else null end AS dst,
case when $.busi_store.BUSI_STORE_NAME IS NOT EMPTY then properties($) else null end AS props;
GO FROM "Tim Duncan" OVER like YIELD like._dst AS dst | FETCH PROP ON * $-.dst YIELD player.age AS age,vertex AS allProperties | ORDER BY $-.age | LIMIT 3 | YIELD $-.allProperties AS allProperties
MATCH (v:table)<–() where not (v:table)–>() RETURN id(v)
(root@nebula) [nba]> """
-> match (v:player) where v.player.age>43
-> match (n:team) where n.team.name starts with "S"
-> with v,n,(v)-->(n) as l
-> return v.player.name,n.team.name,case when size(l)<>0 then true else false end AS hasConnection
-> """
match (v:tag1) return v
match (v)-[e]-(v2) where id(v) == 101 return collect(distinct type(e))
GO FROM <A>/* 这里需要是id */ over com WHERE $^.acc.time >= "" yield e1._dst AS dst, $^.acc.flgid AS flgid
| GO FROM $-.dst OVER com REVERSELY WHERE $^.acc.time >= "" AND $^.acc.timeflg==0 AND $-.flgid=$.comtag.flgid /*其他过滤属性同理*/ YIELD $-.src AS A, com._src AS B
UNION
下面语句的括号记得加上）：(GO FROM a OVER H BIDIRECT YIELD src(edge) as src UNION GO FROM a OVER H BIDIRECT YIELD dst(edge) as src) | GO FROM $-.src OVER H YEILD dst(edge)
MATCH (v)--(v2) WHERE id(v2)=="player100" RETURN DISTINCT id(v)
INTERSECT MATCH (v)--(v2) WHERE id(v2)=="team203" RETURN DISTINCT id(v)
INTERSECT MATCH (v)--(v2) WHERE id(v2)=="player101" RETURN DISTINCT id(v)
按照权重的最短路径 weighted shortest path：
利用了 relationships() 和 reduce() 进行累加
FIND ALL PATH WITH PROP FROM "player100" TO "player101" OVER follow BIDIRECT
YIELD path AS p |
YIELD $-.p, reduce(total_weight = 0, r IN relationships($-.p) | total_weight + r.degree) AS total_weight |
ORDER BY $-.total_weight DESC
ref: Shortest path in directed graph with weights · Issue #4309 · vesoft-inc/nebula · GitHub
Get Subgraph with prop N steps From 'xxx' OUT edgeType WHERE $$.person.is_skip is EMPTY OR $$.person.is_skip == false YIELD vertices AS nodes, edges AS relationships
FIND PATH ... | YIELD nodes($-.path) AS ns, relationships($-.path) AS es
MATCH (uu:player)-[e:follow]->(p:player)-[:serve]->(f:team)
WHERE id(f) == "team204"
WITH p
MATCH ()-[e:follow]->(p:player)
WITH id(p) AS p, e.degree AS degree, count(e) AS count
RETURN p, collect(degree), collect(count)
MATCH p = shortestPath((a)-[e*…5]-(b)), p1 = shortestPath((b)-[e1*…5]-(c))
WHERE id(a) == “player101” and id(b) == “player102” and id(c) == “player105”
RETURN [p,p1];