You do it via the MySQL command prompt (or GUI tools like Navicat, if you have one of those installed).
Using a command prompt, it looks like this:
Code:
C:\Users\Steve>mysql -u root -p peq
Enter password: ******
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.1.31-community MySQL Community Server (GPL)
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql> ALTER TABLE `account` ADD `time_creation` INT UNSIGNED DEFAULT '0' NOT NULL AFTER `suspendeduntil`;
Query OK, 9 rows affected (0.05 sec)
Records: 9 Duplicates: 0 Warnings: 0
mysql> UPDATE `account` SET `time_creation` = UNIX_TIMESTAMP() WHERE `time_creation` = 0;
Query OK, 9 rows affected (0.00 sec)
Rows matched: 9 Changed: 9 Warnings: 0
mysql>
After you enter the mysql -u root ... command, it will ask you for the password you assigned the root user during MySQL installation.