FIND PATH

FIND PATH语句查找指定起始点和目的点之间的路径。

语法

  1. FIND { SHORTEST | ALL | NOLOOP } PATH [WITH PROP] FROM <vertex_id_list> TO <vertex_id_list>
  2. OVER <edge_type_list> [REVERSELY | BIDIRECT] [<WHERE clause>] [UPTO <N> STEPS] [| ORDER BY $-.path] [| LIMIT <M>];
  4. <vertex_id_list> ::=
  5.     [vertex_id [, vertex_id] ...]

  • SHORTEST：查找最短路径。

  • ALL：查找所有路径。

  • NOLOOP：查找非循环路径。

  • WITH PROP：展示点和边的属性。不添加本参数则隐藏属性。

  • <vertex_id_list>：点ID列表。多个点用英文逗号（,）分隔。支持$-和$var。

  • <edge_type_list>：Edge type列表。多个Edge type用英文逗号（,）分隔。*表示所有Edge type。

  • REVERSELY | BIDIRECT：REVERSELY表示反向，BIDIRECT表示双向。

  • <WHERE clause>：可以使用WHERE子句过滤边属性。

  • <N>：路径的最大跳数。默认值为5。

  • <M>：指定返回的最大行数。

限制

  • 指定起始点和目的点的列表后，会返回起始点和目的点所有组合的路径。

  • 搜索所有路径时可能会出现循环。

  • 使用WHERE子句时只能过滤边属性，暂不支持过滤点属性，且不支持函数。

  • 路径的查找是单线程，会占用很多内存。

示例

返回的路径格式类似于(<vertex_id>)-[:<edge_type_name>@<rank>]->(<vertex_id)。

  1. nebula> FIND SHORTEST PATH FROM "player102" TO "team204" OVER *;
  2. +--------------------------------------------+
  3. | path                                       |
  4. +--------------------------------------------+
  5. | <("player102")-[:serve@0 {}]->("team204")> |
  6. +--------------------------------------------+
  1. nebula> FIND SHORTEST PATH WITH PROP FROM "team204" TO "player100" OVER * REVERSELY;
  2. +--------------------------------------------------------------------------------------------------------------------------------------+
  3. | path                                                                                                                                 |
  4. +--------------------------------------------------------------------------------------------------------------------------------------+
  5. | <("team204" :team{name: "Spurs"})<-[:serve@0 {end_year: 2016, start_year: 1997}]-("player100" :player{age: 42, name: "Tim Duncan"})> |
  6. +--------------------------------------------------------------------------------------------------------------------------------------+
  1. nebula> FIND ALL PATH FROM "player100" TO "team204" OVER * WHERE follow.degree is EMPTY or follow.degree >=0;
  2. +------------------------------------------------------------------------------+
  3. | path                                                                         |
  4. +------------------------------------------------------------------------------+
  5. | <("player100")-[:serve@0 {}]->("team204")>                                   |
  6. +------------------------------------------------------------------------------+
  7. | <("player100")-[:follow@0 {}]->("player125")-[:serve@0 {}]->("team204")>     |
  8. +------------------------------------------------------------------------------+
  9. | <("player100")-[:follow@0 {}]->("player101")-[:serve@0 {}]->("team204")>     |
  10. +------------------------------------------------------------------------------+
  11. ...
  1. nebula> FIND NOLOOP PATH FROM "player100" TO "team204" OVER *;
  2. +--------------------------------------------------------------------------------------------------------+
  3. | path                                                                                                   |
  4. +--------------------------------------------------------------------------------------------------------+
  5. | <("player100")-[:serve@0 {}]->("team204")>                                                             |
  6. +--------------------------------------------------------------------------------------------------------+
  7. | <("player100")-[:follow@0 {}]->("player125")-[:serve@0 {}]->("team204")>                               |
  8. +--------------------------------------------------------------------------------------------------------+
  9. | <("player100")-[:follow@0 {}]->("player101")-[:serve@0 {}]->("team204")>                               |
  10. +--------------------------------------------------------------------------------------------------------+
  11. | <("player100")-[:follow@0 {}]->("player101")-[:follow@0 {}]->("player125")-[:serve@0 {}]->("team204")> |
  12. +--------------------------------------------------------------------------------------------------------+
  13. | <("player100")-[:follow@0 {}]->("player101")-[:follow@0 {}]->("player102")-[:serve@0 {}]->("team204")> |
  14. +--------------------------------------------------------------------------------------------------------+

FAQ

是否支持WHERE子句，以实现图遍历过程中的条件过滤?

支持使用WHERE子句过滤，但目前只能过滤边属性，如示例中的FIND ALL PATH FROM "player100" TO "team204" OVER * WHERE follow.degree is EMPTY or follow.degree >=0;。

暂不支持过滤点属性。