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Version: nightly

TABLES

The TABLES table provides information about tables in databases:

USE INFORMATION_SCHEMA;
DESC TABLES;

The output is as follows:

+------------------+----------+------+------+---------+---------------+
| Column           | Type     | Key  | Null | Default | Semantic Type |
+------------------+----------+------+------+---------+---------------+
| table_catalog    | String   |      | NO   |         | FIELD         |
| table_schema     | String   |      | NO   |         | FIELD         |
| table_name       | String   |      | NO   |         | FIELD         |
| table_type       | String   |      | NO   |         | FIELD         |
| table_id         | UInt32   |      | YES  |         | FIELD         |
| data_length      | UInt64   |      | YES  |         | FIELD         |
| max_data_length  | UInt64   |      | YES  |         | FIELD         |
| index_length     | UInt64   |      | YES  |         | FIELD         |
| max_index_length | UInt64   |      | YES  |         | FIELD         |
| avg_row_length   | UInt64   |      | YES  |         | FIELD         |
| engine           | String   |      | YES  |         | FIELD         |
| version          | UInt64   |      | YES  |         | FIELD         |
| row_format       | String   |      | YES  |         | FIELD         |
| table_rows       | UInt64   |      | YES  |         | FIELD         |
| data_free        | UInt64   |      | YES  |         | FIELD         |
| auto_increment   | UInt64   |      | YES  |         | FIELD         |
| create_time      | DateTime |      | YES  |         | FIELD         |
| update_time      | DateTime |      | YES  |         | FIELD         |
| check_time       | DateTime |      | YES  |         | FIELD         |
| table_collation  | String   |      | YES  |         | FIELD         |
| checksum         | UInt64   |      | YES  |         | FIELD         |
| create_options   | String   |      | YES  |         | FIELD         |
| table_comment    | String   |      | YES  |         | FIELD         |
| temporary        | String   |      | YES  |         | FIELD         |
+------------------+----------+------+------+---------+---------------+
SELECT * FROM tables WHERE table_schema='public' AND table_name='monitor'\G
*************************** 1. row ***************************
   table_catalog: greptime
    table_schema: public
      table_name: monitor
      table_type: BASE TABLE
        table_id: 1054
     data_length: 0
 max_data_length: 0
    index_length: 0
max_index_length: 0
  avg_row_length: 0
          engine: mito
         version: 11
      row_format: Fixed
      table_rows: 0
       data_free: 0
  auto_increment: 0
     create_time: 2024-07-24 22:06:18.085000
     update_time: NULL
      check_time: NULL
 table_collation: NULL
        checksum: 0
  create_options:
   table_comment: NULL
       temporary: N
1 row in set (0.01 sec)

The following statements are equivalent:

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

SHOW TABLES
  FROM db_name
  [LIKE 'monitor']

The description of columns in the TABLES table is as follows:

  • table_catalog: The catalog to which the table belongs. The value is always greptime.
  • table_schema: The database to which the table belongs.
  • table_name: The name of the table.
  • table_type: The type of the table.
    • BASE TABLE for a table.
    • TEMPORARY for a temporary result set.
    • VIEW for a view.
  • table_id: The ID of the table.
  • data_length: The total length of the table's SST files in bytes, which is an approximate value.
  • index_length: The total length of the table's index files in bytes, which is an approximate value.
  • table_rows: The table's total row number, which is an approximate value.
  • avg_row_length: The average row length in bytes, which is an approximate value.
  • engine: The storage engine of the table used.
  • version: Version. The value is 11 by default.
  • create_time: The table created timestamp.
  • table_comment: The table comment.
  • Other columns such as auto_increment, row_format etc. are not supported, just for compatibility with MySQL. GreptimeDB may support some of them in the future.