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全文搜索

全文搜索是基于全文索引对值为字符串类型的属性进行前缀搜索、通配符搜索、正则表达式搜索和模糊搜索。

LOOKUPMATCH语句中,使用WHERE子句指定字符串的搜索条件。

前提条件

请确保已经部署全文索引。详情请参见部署全文索引部署listener

注意事项

使用全文索引前,请确认已经了解全文索引的使用限制

自然语言全文搜索

自然语言搜索将搜索的字符串解释为自然人类语言中的短语。搜索不区分大小写。

语法

LOOKUP ON {<tag> | <edge_type>} WHERE <expression> [YIELD <return_list>];

<expression> ::=
    PREFIX | WILDCARD | REGEXP | FUZZY

<return_list>
    <prop_name> [AS <prop_alias>] [, <prop_name> [AS <prop_alias>] ...]
  • PREFIX(schema_name.prop_name, prefix_string, row_limit, timeout)
  • WILDCARD(schema_name.prop_name, wildcard_string, row_limit, timeout)
  • REGEXP(schema_name.prop_name, regexp_string, row_limit, timeout)
  • FUZZY(schema_name.prop_name, fuzzy_string, fuzziness, operator, row_limit, timeout)

    • fuzziness:可选项。允许匹配的最大编辑距离。默认值为AUTO。查看其他可选值和更多信息,请参见Elasticsearch官方文档
    • operator:可选项。解释文本的布尔逻辑。可选值为OR(默认)和and
  • row_limit:可选项。指定要返回的行数。默认值为100
  • timeout:可选项。指定超时时间。单位:毫秒(ms)。默认值为200

示例

nebula> CREATE SPACE basketballplayer (partition_num=3,replica_factor=1, vid_type=fixed_string(30));
nebula> SIGN IN TEXT SERVICE (127.0.0.1:9200);
nebula> USE basketballplayer;
nebula> ADD LISTENER ELASTICSEARCH 192.168.8.5:46780;
nebula> CREATE TAG player(name string, age int);
nebula> CREATE TAG INDEX name ON player(name(20));
nebula> INSERT VERTEX player(name, age) VALUES \
  "Russell Westbrook": ("Russell Westbrook", 30), \
  "Chris Paul": ("Chris Paul", 33),\
  "Boris Diaw": ("Boris Diaw", 36),\
  "David West": ("David West", 38),\
  "Danny Green": ("Danny Green", 31),\
  "Tim Duncan": ("Tim Duncan", 42),\
  "James Harden": ("James Harden", 29),\
  "Tony Parker": ("Tony Parker", 36),\
  "Aron Baynes": ("Aron Baynes", 32),\
  "Ben Simmons": ("Ben Simmons", 22),\
  "Blake Griffin": ("Blake Griffin", 30);


nebula> LOOKUP ON player WHERE PREFIX(player.name, "B");
+-----------------+
| _vid            |
+-----------------+
| "Boris Diaw"    |
+-----------------+
| "Ben Simmons"   |
+-----------------+
| "Blake Griffin" |
+-----------------+

nebula> LOOKUP ON player WHERE WILDCARD(player.name, "*ri*") YIELD player.name, player.age;
+-----------------+-----------------+-----+
| _vid            | name            | age |
+-----------------+-----------------+-----+
| "Chris Paul"    | "Chris Paul"    | 33  |
+-----------------+-----------------+-----+
| "Boris Diaw"    | "Boris Diaw"    | 36  |
+-----------------+-----------------+-----+
| "Blake Griffin" | "Blake Griffin" | 30  |
+-----------------+-----------------+-----+

nebula> LOOKUP ON player WHERE WILDCARD(player.name, "*ri*") | YIELD count(*);
+----------+
| COUNT(*) |
+----------+
| 3        |
+----------+

nebula> LOOKUP ON player WHERE REGEXP(player.name, "R.*") YIELD player.name, player.age;
+---------------------+---------------------+-----+
| _vid                | name                | age |
+---------------------+---------------------+-----+
| "Russell Westbrook" | "Russell Westbrook" | 30  |
+---------------------+---------------------+-----+

nebula> LOOKUP ON player WHERE REGEXP(player.name, ".*");
+---------------------+
| _vid                |
+---------------------+
| "Danny Green"       |
+---------------------+
| "David West"        |
+---------------------+
| "Russell Westbrook" |
+---------------------+
...

nebula> LOOKUP ON player WHERE FUZZY(player.name, "Tim Dunncan", AUTO, OR) YIELD player.name;
+--------------+--------------+
| _vid         | name         |
+--------------+--------------+
| "Tim Duncan" | "Tim Duncan" |
+--------------+--------------+

最后更新: 2021年5月14日