编码引起的SQL注入问题总结
Reference
https://security.stackexchange.com/questions/9908/multibyte-character-exploits-php-mysql
https://www.erich-kachel.de/unicode-issues-on-php/
https://vigilance.fr/vulnerability/MySQL-SQL-injection-via-multi-byte-characters-5885
http://shiflett.org/blog/2006/addslashes-versus-mysql-real-escape-string
https://stackoverflow.com/questions/5741187/sql-injection-that-gets-around-mysql-real-escape-string/12118602#12118602
http://eleves.ec-lille.fr/~couprieg/post/Bypass-addslashes-with-UTF-8-characters