字符串运算符¶
Nebula Graph 支持使用字符串运算符进行连接、搜索、匹配运算。支持的运算符如下。
| 名称 | 说明 |
|---|---|
| + | 连接字符串。 |
| CONTAINS | 在字符串中执行搜索。 |
| (NOT) IN | 字符串是否匹配某个值。 |
| (NOT) STARTS WITH | 在字符串的开头执行匹配。 |
| (NOT) ENDS WITH | 在字符串的结尾执行匹配。 |
| 正则表达式 | 通过正则表达式匹配字符串。 |
Note
所有搜索或匹配都区分大小写。
示例¶
+¶
ngql
nebula> RETURN 'a' + 'b';
+-----------+
| ("a"+"b") |
+-----------+
| "ab" |
+-----------+
nebula> UNWIND 'a' AS a UNWIND 'b' AS b RETURN a + b;
+-------+
| (a+b) |
+-------+
| "ab" |
+-------+
CONTAINS¶
CONTAINS要求待运算的左右两边都是字符串类型。
```ngql nebula> MATCH (s:player)-[e:serve]->(t:team) WHERE id(s) == "player101" \ AND t.team.name CONTAINS "ets" RETURN s.player.name, e.start_year, e.end_year, t.team.name; +---------------+--------------+------------+-------------+ | s.player.name | e.start_year | e.end_year | t.team.name | +---------------+--------------+------------+-------------+ | "Tony Parker" | 2018 | 2019 | "Hornets" | +---------------+--------------+------------+-------------+
nebula> GO FROM "player101" OVER serve WHERE (STRING)properties(edge).start_year CONTAINS "19" AND \ properties(\(^).name CONTAINS "ny" \ YIELD properties(\)^).name, properties(edge).start_year, properties(edge).end_year, properties(\(\().name; +---------------------+-----------------------------+---------------------------+---------------------+ | properties(\)^).name | properties(EDGE).start_year | properties(EDGE).end_year | properties(\)$).name | +---------------------+-----------------------------+---------------------------+---------------------+ | "Tony Parker" | 1999 | 2018 | "Spurs" | +---------------------+-----------------------------+---------------------------+---------------------+
nebula> GO FROM "player101" OVER serve WHERE !(properties(\(\().name CONTAINS "ets") \ YIELD properties(\)^).name, properties(edge).start_year, properties(edge).end_year, properties(\)\().name; +---------------------+-----------------------------+---------------------------+---------------------+ | properties(\)^).name | properties(EDGE).start_year | properties(EDGE).end_year | properties($$).name | +---------------------+-----------------------------+---------------------------+---------------------+ | "Tony Parker" | 1999 | 2018 | "Spurs" | +---------------------+-----------------------------+---------------------------+---------------------+ ```
(NOT) IN¶
ngql
nebula> RETURN 1 IN [1,2,3], "Yao" NOT IN ["Yi", "Tim", "Kobe"], NULL IN ["Yi", "Tim", "Kobe"];
+----------------+------------------------------------+-------------------------------+
| (1 IN [1,2,3]) | ("Yao" NOT IN ["Yi","Tim","Kobe"]) | (NULL IN ["Yi","Tim","Kobe"]) |
+----------------+------------------------------------+-------------------------------+
| true | true | __NULL__ |
+----------------+------------------------------------+-------------------------------+
(NOT) STARTS WITH¶
```ngql nebula> RETURN 'apple' STARTS WITH 'app', 'apple' STARTS WITH 'a', 'apple' STARTS WITH toUpper('a'); +-----------------------------+---------------------------+------------------------------------+ | ("apple" STARTS WITH "app") | ("apple" STARTS WITH "a") | ("apple" STARTS WITH toUpper("a")) | +-----------------------------+---------------------------+------------------------------------+ | true | true | false | +-----------------------------+---------------------------+------------------------------------+
nebula> RETURN 'apple' STARTS WITH 'b','apple' NOT STARTS WITH 'app'; +---------------------------+---------------------------------+ | ("apple" STARTS WITH "b") | ("apple" NOT STARTS WITH "app") | +---------------------------+---------------------------------+ | false | false | +---------------------------+---------------------------------+ ```
(NOT) ENDS WITH¶
ngql
nebula> RETURN 'apple' ENDS WITH 'app', 'apple' ENDS WITH 'e', 'apple' ENDS WITH 'E', 'apple' ENDS WITH 'b';
+---------------------------+-------------------------+-------------------------+-------------------------+
| ("apple" ENDS WITH "app") | ("apple" ENDS WITH "e") | ("apple" ENDS WITH "E") | ("apple" ENDS WITH "b") |
+---------------------------+-------------------------+-------------------------+-------------------------+
| false | true | false | false |
+---------------------------+-------------------------+-------------------------+-------------------------+
正则表达式¶
Note
当前仅 opencypher 兼容语句（MATCH、WITH等）支持正则表达式，原生 nGQL 语句（FETCH、GO、LOOKUP等）不支持正则表达式。
Nebula Graph 支持使用正则表达式进行过滤，正则表达式的语法是继承自std::regex，用户可以使用语法=~ '<regexp>'进行正则表达式匹配。例如：
```ngql nebula> RETURN "384748.39" =~ "\d+(\.\d{2})?"; +--------------------------------+ | ("384748.39"=~"\d+(.\d{2})?") | +--------------------------------+ | true | +--------------------------------+
nebula> MATCH (v:player) WHERE v.player.name =~ 'Tony.*' RETURN v.player.name; +---------------+ | v.player.name | +---------------+ | "Tony Parker" | +---------------+ ```