start mysql through two ways.

1./etc/init.d/mysql restart

2.mysql -u root

other tips

mysql> SET PASSWORD FOR 'root'@'localhost' = PASSWORD('yourpassword');

mysql>\q;  quit mysql

mysql>create database databasename;

mysql>drop datebase databasename;||drop schema databasename;
This means to delete the existed database.

mysql>show databases;
mysql>use datebase;
mysql>show tables;
mysql>create table tablename();

For example:
mysql> CREATE TABLE grocery_inventory (
    -> id int not null primary key auto_increment,
    -> item_name varchar (50) not null,
    -> item_desc text,
    -> item_price float not null,
    -> curr_qty int not null
    -> );

For example:
mysql>use mysql;
mysql>select * from  person;
mysql> insert into person (id,firstname,lastname) values(106,'peter','wang');

Note:don't forget a semicolon(;) at the end of the statements.

There is a good web address'http://www.webdevelopersnotes.com/tutorials/sql/index.php3'