(1).select

显示当前日期和时间

mysql> select now();

+---------------------+

| now() |

+---------------------+

| 2019-06-05 13:46:20 |

+---------------------+

1 row in set (0.00 sec)

显示当前日期

mysql> select curdate();

+------------+

| curdate() |

+------------+

| 2019-06-05 |

+------------+

1 row in set (0.04 sec)

显示当前时间

mysql> select curtime();

+-----------+

| curtime() |

+-----------+

| 13:48:15 |

+-----------+

1 row in set (0.00 sec)

显示当前所在数据库

mysql> use test_db;

Reading table information for completion of table and column names

You can turn off this feature to get a quicker startup with -A

Database changed

mysql> select database();

+------------+

| database() |

+------------+

| test_db |

+------------+

1 row in set (0.00 sec)

显示Mysql版本

mysql> select version();

+-----------+

| version() |

+-----------+

| 5.7.16 |

+-----------+

1 row in set (0.00 sec)

显示当前用户

mysql> select user();

+----------------+

| user() |

+----------------+

| root@localhost |

+----------------+

1 row in set (0.00 sec)

(2).show

show variables;显示变量

show global variables;显示全局变量

show global variables like '%version%';显示版本信息

mysql> show global variables like '%version%';

+-------------------------+------------------------------+

| Variable_name | Value |

+-------------------------+------------------------------+

| innodb_version | 5.7.16 |

| protocol_version | 10 |

| slave_type_conversions | |

| tls_version | TLSv1,TLSv1.1 |

| version | 5.7.16 |

| version_comment | MySQL Community Server (GPL) |

| version_compile_machine | x86_64 |

| version_compile_os | Linux |

+-------------------------+------------------------------+

8 rows in set (0.00 sec)

show variables like '%storage_engine%';显示默认的存储引擎

mysql> show variables like '%storage_engine%';

+----------------------------------+--------+

| Variable_name | Value |

+----------------------------------+--------+

| default_storage_engine | InnoDB |

| default_tmp_storage_engine | InnoDB |

| disabled_storage_engines | |

| internal_tmp_disk_storage_engine | InnoDB |

+----------------------------------+--------+

4 rows in set (0.00 sec)