I was updating phpBB3 when I ran into a small problem. My database was not up to date. I got this message:
I clicked on the link on the update page and it led me to http://www.phpbb.com/kb/article/doesnt-have-a-default-value-errors/
I downloaded mysql_upgrader.php for my version of phpBB3 which is 3.05
I open the mysql_upgrader.php file with notepad, and deleted this line
die(“Please read the first lines of this script for instructions on how to enable it”);
and saved my file, and uploaded it to my root directory of phpbb.
All I had to do was visit example.com/mysql_upgrader.php
copy all the SQL code on the SQL command  text box, and run the code in phpmyadmin SQL textbox which you enter by clicking the SQL icon after you logged into PhpmyAdmin control panel for your mySQL database.
Lastly, I deleted the mysql_upgrader.php file and now I can continue my phpBB3 update from phpBB3 admin panel.