Common useful mysql commands

use root account to login to database "mysql"
# mysql -u root mysql

Show all fields of a selected table
mysql> desc user;

mysql> select User,Host from mysql.user;

Some on-line help
mysql> help contents;
You asked for help about help category: "Contents"
For more information, type 'help ', where is one of the following
categories:
Account Management
Administration
Data Definition
Data Manipulation
Data Types
Functions
Functions and Modifiers for Use with GROUP BY
Geographic Features
Language Structure
Storage Engines
Stored Routines
Table Maintenance
Transactions
Triggers

mysql> Update user SET Insert_priv='y',Update_priv='y' where user='openser'; Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0

# Before update the value. Show the record value of specified field in a indicated record (user)
mysql> Select User,Select_priv,Insert_priv,Update_priv,Delete_priv,Create_priv,Drop_priv,Reload_priv From user WHERE user='openser';
+---------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+
| User | Select_priv | Insert_priv | Update_priv | Delete_priv | Create_priv | Drop_priv | Reload_priv |
+---------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+
| openser | Y | Y | Y | N | N | N | N |
+---------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+
1 row in set (0.00 sec)

# Update the value of specified field in a indicated record (user)
mysql> Update user SET Delete_priv='y',Create_priv='y',Drop_priv='y',Reload_priv='y' where user='openser'; Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0

# After update the value. Show the record value of specified field in a indicated record (user)
mysql> Select User,Select_priv,Insert_priv,Update_priv,Delete_priv,Create_priv,Drop_priv,Reload_priv From user WHERE user='openser';
+---------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+
| User | Select_priv | Insert_priv | Update_priv | Delete_priv | Create_priv | Drop_priv | Reload_priv |
+---------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+
| openser | Y | Y | Y | Y | Y | Y | Y |
+---------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+
1 row in set (0.00 sec)