只有这个代码对我有用

/usr/local/mysql/bin/mysql -V  

mysqladmin版本或mysqladmin -V

SHOW VARIABLES LIKE "%version%";
+-------------------------+------------------------------------------+
| Variable_name           | Value                                    |
+-------------------------+------------------------------------------+
| protocol_version        | 10                                       |
| version                 | 5.0.27-standard                          |
| version_comment         | MySQL Community Edition - Standard (GPL) |
| version_compile_machine | i686                                     |
| version_compile_os      | pc-linux-gnu                             |
+-------------------------+------------------------------------------+
5 rows in set (0.04 sec)

MySQL 5.0参考手册(pdf) -确定您当前的MySQL版本-第42页

简单的登录到Mysql用

mysql -u root -p

然后输入这个命令

select @@version;

得到的结果是，

+-------------------------+
| @@version               |
+-------------------------+
| 5.7.16-0ubuntu0.16.04.1 |
+-------------------------+
1 row in set (0.00 sec)

您还可以在第一次登录时查看MySQL shell的顶部。它实际上在这里显示了版本。

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 67971
Server version: 5.1.73 Source distribution

Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>

Xampp与Windows用户在下面的命令中工作在mysql目录。