A few useful sql functions

Start mysql in Ubuntu without having root privilege:-
If you want to use mysql in Ubutu you can use following command which will use a root level privilege  
$ mysql -u root -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 147
Server version: 5.1.49-1ubuntu8.1-log (Ubuntu)
When it demands to enter the password fill it with 'root' and hopefully you'll get logged in .  

Last_insert_id():- (with no argument) returns the first automatically generated value that was set for an AUTO_INCREMENT column by the most recently executed INSERT statement to affect such a column. For example, after inserting a row that generates an AUTO_INCREMENT value, you can get the value like this: 
mysql> SELECT LAST_INSERT_ID();


Database():-
Database() method returns the current selected database and you can use it in your communication and your queries. The syntax is :
 mysql>select Database ();

User():-
It also has synonym named  Session_user() and System_user() which returns the current user who is using the mysql along with the hostname.
mysql>select user();