MySQL中查看MySQL相关信息

（参考）http://www.jb51.net/article/36356.htm

（1）VERSION()返回数据库版本号

mysql> select VERSION();
+-----------+
| VERSION() |
+-----------+
| 5.5.8-log |
+-----------+
1 row in set (0.00 sec)

（2）CONNECTION_ID()返回数据库的连接次数

mysql> select CONNECTION_ID();
+-----------------+
| CONNECTION_ID() |
+-----------------+
|              40 |
+-----------------+
1 row in set (0.02 sec)

（3）DATABASE()、SCHEMA()返回当前数据库名

mysql> select DATABASE(), SCHEMA();
+------------+----------+
| DATABASE() | SCHEMA() |
+------------+----------+
| test       | test     |
+------------+----------+
1 row in set (0.00 sec)

mysql>

（4）USER()、SYSTEM_USER()、SESSION_USER()返回当前用户

mysql> select USER(), SYSTEM_USER(), SESSION_USER();
+----------------+----------------+----------------+
| USER()         | SYSTEM_USER()  | SESSION_USER() |
+----------------+----------------+----------------+
| root@localhost | root@localhost | root@localhost |
+----------------+----------------+----------------+
1 row in set (0.00 sec)

mysql>

（5）CURRENT_USER()、CURRENT_USER返回当前用户

mysql> select CURRENT_USER(), CURRENT_USER;
+----------------+----------------+
| CURRENT_USER() | CURRENT_USER   |
+----------------+----------------+
| root@localhost | root@localhost |
+----------------+----------------+
1 row in set (0.00 sec)

mysql>

（6）CHARSET(str)返回字符串str的字符集

mysql> select CHARSET('MySQL');
+------------------+
| CHARSET('MySQL') |
+------------------+
| utf8             |
+------------------+
1 row in set (0.00 sec)

mysql>

（7）COLLATION(str)返回字符串str的字符排列方式

mysql> select COLLATION('MySQL');
+--------------------+
| COLLATION('MySQL') |
+--------------------+
| utf8_general_ci    |
+--------------------+
1 row in set (0.00 sec)

mysql>