The following errors are shown during a 2.2.x to 2.3 upgrade:
WordPress database error: [Field 'option_description' doesn't have a default value]
INSERT INTO wp_options (option_name, option_value, autoload) VALUES ('new_users_can_blog', '0', 'yes')
WordPress database error: [Field 'option_description' doesn't have a default value]
INSERT INTO wp_options (option_name, option_value, autoload) VALUES ('tag_base', '', 'yes')
This is caused by calling populate_options before upgrade_230_options_table during the upgrade.