出现错误：

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘) ENGINE=MyISAM DEFAULT CHARSET=utf8’ at line 19

经检查出错文件是：

protected/install/database/update/003/add_mentions_table.sql

该 SQL 语句多了一个逗号，将 UNIQUE KEY `item` USING BTREE (`source_id`, `item_id`, `url`), 后的逗号去掉即可。