SHOW
更新時(shí)間：
您可以通過(guò)SHOW語(yǔ)句查看數(shù)據(jù)庫(kù)相關(guān)信息，例如數(shù)據(jù)庫(kù)列表、數(shù)據(jù)庫(kù)中的表以及表中的列或索引等。
SHOW DATABASES
查看當(dāng)前集群中的數(shù)據(jù)庫(kù)。
語(yǔ)法
SHOW DATABASES; 示例
SHOW DATABASES;返回結(jié)果如下：
+--------------------+
| Database |
+--------------------+
| adb_test |
| MYSQL |
| adb_demo |
| INFORMATION_SCHEMA |
+--------------------+SHOW TABLES
查看用戶(hù)當(dāng)前數(shù)據(jù)庫(kù)中的表。
語(yǔ)法
SHOW TABLES [IN db_name]; 示例
SHOW TABLES IN adb_demo;返回結(jié)果如下：
+--------------------+
| Tables_in_adb_demo |
+--------------------+
| customer |
| json_test |
+--------------------+SHOW COLUMNS
查看表的列信息。
語(yǔ)法
SHOW COLUMNS IN db_name.table_name； 示例
SHOW COLUMNS IN adb_demo.customer;返回結(jié)果如下：
+---------+---------+------+------+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+---------+---------+------+------+---------+-------+
| id | int | NO | PRI | NULL | |
| name | varchar | YES | | NULL | |
| address | varchar | YES | | NULL | |
| gender | boolean | YES | | NULL | |
+---------+---------+------+------+---------+-------+SHOW CREATE TABLE
查看表的建表語(yǔ)句。
語(yǔ)法
SHOW CREATE TABLE db_name.table_name; 示例
SHOW CREATE TABLE adb_demo.customer;返回結(jié)果如下：
+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| customer | Create Table `customer` (
`id` int NOT NULL,
`name` varchar(50),
`address` varchar(80),
`gender` boolean,
primary key (`id`)
) DISTRIBUTE BY HASH(`id`) INDEX_ALL='Y' STORAGE_POLICY='HOT' BLOCK_SIZE=8192 |
+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+SHOW GRANTS
查看用戶(hù)的權(quán)限。
語(yǔ)法
SHOW GRANTS [FOR 'username'@'hostname'];其中，username為用戶(hù)名，hostname為主機(jī)名或主機(jī)IP。
示例
查看當(dāng)前用戶(hù)的權(quán)限，無(wú)需指定用戶(hù)名和主機(jī)。
SHOW GRANTS;返回結(jié)果如下：
+---------------------------------------------------------+ | Grants for adb_acc@% | +---------------------------------------------------------+ | GRANT ALL ON `*`.`*` TO 'adb_acc'@'%' WITH GRANT OPTION | +---------------------------------------------------------+查看指定用戶(hù)的權(quán)限。
SHOW GRANTS FOR 'test'@'%';返回結(jié)果如下：
+---------------------------------------------------------+ | Grants for test@% | +---------------------------------------------------------+ | GRANT ALL ON `*`.`*` TO 'adb'@'%' WITH GRANT OPTION | +---------------------------------------------------------+
SHOW INDEXES
查看表的索引信息。
語(yǔ)法
SHOW INDEXES FROM db_name.table_name; 示例
SHOW INDEXES FROM adb_demo.json_test;返回結(jié)果如下，其中Key_name即為索引名：
+-----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+-----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| json_test | 1 | id_0_idx | 1 | id | A | 0 | NULL | NULL | | BTREE | | |
| json_test | 1 | vj_idx | 1 | vj | A | 0 | NULL | NULL | | BTREE | | |
+-----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+文檔內(nèi)容是否對(duì)您有幫助？