TABLES
TABLES
表提供数据库中表的信息:
USE INFORMATION_SCHEMA;
DESC TABLES;
结果如下:
+------------------+----------+------+------+---------+---------------+
| 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)
下方的语句是等价的:
SELECT table_name FROM INFORMATION_SCHEMA.TABLES
WHERE table_schema = '<db_name>'
[AND table_name LIKE 'monitor']
SHOW TABLES
FROM db_name
[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。data_length
: 表中 SST 文件的总长度(以字节为单位),近似值。index_length
: 表中索引文件的总长度(以字节为单位),近似值。table_rows
: 表中总的记录行数,近似值。avg_row_length
: 表中记录的平均大小(以字节为单位),近似值。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。