Create MySQL中字符串函数详细介绍

http://www.lampblog.net/2010/11/mysql%E4%B8%AD%E5%AD%97%E7%AC%A6%E4%B8%B2%E5%87%BD%E6%95%B0%E8%AF%A6%E7%BB%86%E4%BB%8B%E7%BB%8D/