TABLES

TABLES 表提供数据库中表的信息：

1. USE INFORMATION_SCHEMA;
2. DESC TABLES;

结果如下：

1. +------------------+----------+------+------+---------+---------------+
2. | Column           | Type     | Key  | Null | Default | Semantic Type |
3. +------------------+----------+------+------+---------+---------------+
4. | table_catalog    | String   |      | NO   |         | FIELD         |
5. | table_schema     | String   |      | NO   |         | FIELD         |
6. | table_name       | String   |      | NO   |         | FIELD         |
7. | table_type       | String   |      | NO   |         | FIELD         |
8. | table_id         | UInt32   |      | YES  |         | FIELD         |
9. | data_length      | UInt64   |      | YES  |         | FIELD         |
10. | max_data_length  | UInt64   |      | YES  |         | FIELD         |
11. | index_length     | UInt64   |      | YES  |         | FIELD         |
12. | max_index_length | UInt64   |      | YES  |         | FIELD         |
13. | avg_row_length   | UInt64   |      | YES  |         | FIELD         |
14. | engine           | String   |      | YES  |         | FIELD         |
15. | version          | UInt64   |      | YES  |         | FIELD         |
16. | row_format       | String   |      | YES  |         | FIELD         |
17. | table_rows       | UInt64   |      | YES  |         | FIELD         |
18. | data_free        | UInt64   |      | YES  |         | FIELD         |
19. | auto_increment   | UInt64   |      | YES  |         | FIELD         |
20. | create_time      | DateTime |      | YES  |         | FIELD         |
21. | update_time      | DateTime |      | YES  |         | FIELD         |
22. | check_time       | DateTime |      | YES  |         | FIELD         |
23. | table_collation  | String   |      | YES  |         | FIELD         |
24. | checksum         | UInt64   |      | YES  |         | FIELD         |
25. | create_options   | String   |      | YES  |         | FIELD         |
26. | table_comment    | String   |      | YES  |         | FIELD         |
27. | temporary        | String   |      | YES  |         | FIELD         |
28. +------------------+----------+------+------+---------+---------------+

1. SELECT * FROM tables WHERE table_schema='public' AND table_name='monitor'\G

1. *************************** 1. row ***************************
2. table_catalog: greptime
3. table_schema: public
4. table_name: monitor
5. table_type: BASE TABLE
6. table_id: 1054
7. data_length: 0
8. max_data_length: 0
9. index_length: 0
10. max_index_length: 0
11. avg_row_length: 0
12. engine: mito
13. version: 11
14. row_format: Fixed
15. table_rows: 0
16. data_free: 0
17. auto_increment: 0
18. create_time: 2024-07-24 22:06:18.085000
19. update_time: NULL
20. check_time: NULL
21. table_collation: NULL
22. checksum: 0
23. create_options:
24. table_comment: NULL
25. temporary: N
26. 1 row in set (0.01 sec)

下方的语句是等价的：

1. SELECT table_name FROM INFORMATION_SCHEMA.TABLES
2. WHERE table_schema = '<db_name>'
3. [AND table_name LIKE 'monitor']

5. SHOW TABLES
6. FROM db_name
7. [LIKE 'monitor']

TABLES 表的字段描述如下：

  • table_catalog：表所属的目录。该值始终为 greptime。
  • table_schema：表所属的数据库。
  • table_name：表的名称。
  • table_type：表的类型。
  • BASE TABLE：基础表
  • TEMPORARY：临时结果集
  • VIEW：视图表
  • table_id：表 ID。
  • engine：该表使用的存储引擎。
  • version: 版本。固定值为 11。
  • create_time: 表创建的时间戳。
  • table_comment: 表的注释。
  • 其他列如 table_rows， row_format 等不支持，仅用于兼容 MySQL。GreptimeDB 未来可能会支持其中的一些列。