https://juejin.im/post/5cad39b3f265da03502b1c0a#heading-5
1. 查看用户：
mysql> use mysql;
mysql> select host,user from mysql.user;
+------------+------+
| host | user |
+------------+------+
| 127.0.0.1 | root |
| ::1 | root |
| localhost | |
| localhost | root |
| server.gao | |
| server.gao | root |
+------------+------+
2. 创建用户:
mysql> create user 'usrabc'@'%' identified by 'usrabc';
mysql> select host,user from mysql.user;
+------------+--------+
| host | user |
+------------+--------+
| % | usrabc |
| 127.0.0.1 | root |
| ::1 | root |
| localhost | |
| localhost | root |
| server.gao | |
| server.gao | root |
+------------+--------+
3. 查看当前登录用户
mysql> select user();
+----------------+
| user() |
+----------------+
| root@localhost |
+----------------+
1 row in set (0.00 sec)
4. 查看当前数据库
mysql> select database();
+--------------------+
| database() |
+--------------------+
| information_schema |
+--------------------+
1 row in set (0.00 sec)
4. 删除用户
mysql> use mysql;
mysql> DELETE FROM user WHERE HOST='localhost' AND User="test2";
+------------+------+
| host | user |
+------------+------+
| 127.0.0.1 | root |
| ::1 | root |
| localhost | |
+------------+------+
query OK;
