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。

在LOOKUP或MATCH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和部署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

  1. LOOKUP ON {<tag> | <edge_type>} WHERE <expression> [YIELD <return_list>];
  3. <expression> ::=
  4.     PREFIX | WILDCARD | REGEXP | FUZZY
  6. <return_list>
  7.     <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

  1. nebula> CREATE SPACE basketballplayer (partition_num=3,replica_factor=1, vid_type=fixed_string(30));
  2. nebula> SIGN IN TEXT SERVICE (127.0.0.1:9200);
  3. nebula> USE basketballplayer;
  4. nebula> ADD LISTENER ELASTICSEARCH 192.168.8.5:46780;
  5. nebula> CREATE TAG player(name string, age int);
  6. nebula> CREATE TAG INDEX name ON player(name(20));
  7. nebula> INSERT VERTEX player(name, age) VALUES \
  8.   "Russell Westbrook": ("Russell Westbrook", 30), \
  9.   "Chris Paul": ("Chris Paul", 33),\
  10.   "Boris Diaw": ("Boris Diaw", 36),\
  11.   "David West": ("David West", 38),\
  12.   "Danny Green": ("Danny Green", 31),\
  13.   "Tim Duncan": ("Tim Duncan", 42),\
  14.   "James Harden": ("James Harden", 29),\
  15.   "Tony Parker": ("Tony Parker", 36),\
  16.   "Aron Baynes": ("Aron Baynes", 32),\
  17.   "Ben Simmons": ("Ben Simmons", 22),\
  18.   "Blake Griffin": ("Blake Griffin", 30);
  21. nebula> LOOKUP ON player WHERE PREFIX(player.name, "B");
  22. +-----------------+
  23. | _vid            |
  24. +-----------------+
  25. | "Boris Diaw"    |
  26. +-----------------+
  27. | "Ben Simmons"   |
  28. +-----------------+
  29. | "Blake Griffin" |
  30. +-----------------+
  32. nebula> LOOKUP ON player WHERE WILDCARD(player.name, "*ri*") YIELD player.name, player.age;
  33. +-----------------+-----------------+-----+
  34. | _vid            | name            | age |
  35. +-----------------+-----------------+-----+
  36. | "Chris Paul"    | "Chris Paul"    | 33  |
  37. +-----------------+-----------------+-----+
  38. | "Boris Diaw"    | "Boris Diaw"    | 36  |
  39. +-----------------+-----------------+-----+
  40. | "Blake Griffin" | "Blake Griffin" | 30  |
  41. +-----------------+-----------------+-----+
  43. nebula> LOOKUP ON player WHERE WILDCARD(player.name, "*ri*") | YIELD count(*);
  44. +----------+
  45. | COUNT(*) |
  46. +----------+
  47. | 3        |
  48. +----------+
  50. nebula> LOOKUP ON player WHERE REGEXP(player.name, "R.*") YIELD player.name, player.age;
  51. +---------------------+---------------------+-----+
  52. | _vid                | name                | age |
  53. +---------------------+---------------------+-----+
  54. | "Russell Westbrook" | "Russell Westbrook" | 30  |
  55. +---------------------+---------------------+-----+
  57. nebula> LOOKUP ON player WHERE REGEXP(player.name, ".*");
  58. +---------------------+
  59. | _vid                |
  60. +---------------------+
  61. | "Danny Green"       |
  62. +---------------------+
  63. | "David West"        |
  64. +---------------------+
  65. | "Russell Westbrook" |
  66. +---------------------+
  67. ...
  69. nebula> LOOKUP ON player WHERE FUZZY(player.name, "Tim Dunncan", AUTO, OR) YIELD player.name;
  70. +--------------+--------------+
  71. | _vid         | name         |
  72. +--------------+--------------+
  73. | "Tim Duncan" | "Tim Duncan" |
  74. +--------------+--------------+