字符串运算符¶
NebulaGraph 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¶
+
¶
# 返回连接后的字符串。
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。
# 查询返回 id 值为 player101,且目标点属性 name 中含有"ets"的数据。
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" |
+---------------+--------------+------------+-------------+
# 查询返回 player101 的边属性 start_year 转为字符串后含有"19",且点属性 name 中含有"ny"的数据。
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" |
+---------------------+-----------------------------+---------------------------+---------------------+
# 查询返回 palyer101 指向的目标点属性 name 中不含有"ets"的数据。
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
¶
# 返回列表中是否含有某个值。
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
¶
# 返回是否以某个字符串开头。
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
¶
# 返回是否以某个字符串结尾。
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。
NebulaGraph 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:
# 返回是否匹配正则表达式。
nebula> RETURN "384748.39" =~ "\\d+(\\.\\d{2})?";
+--------------------------------+
| ("384748.39"=~"\d+(\.\d{2})?") |
+--------------------------------+
| true |
+--------------------------------+
# 查询返回符合正则表达式的点数据。
nebula> MATCH (v:player) WHERE v.player.name =~ 'Tony.*' RETURN v.player.name;
+---------------+
| v.player.name |
+---------------+
| "Tony Parker" |
+---------------+
最后更新:
2024年9月14日