中文用户名登陆有误，字符编码问题，怎么弄？

[Type] 查询语句错误
  [1267] Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8_general_ci,COERCIBLE) for operation '='
  [Query] SELECT count, lastupdate FROM common_failedlogin WHERE ip='218.79.226.160' AND username='上海'

Program messages:  

  [Line: 0030]admin.php(discuz_admincp->init)
  [Line: 0056]source/class/class_admincp.php(discuz_admincp->check_cpaccess)
  [Line: 0124]source/class/class_admincp.php(discuz_admincp->check_user_login)
  [Line: 0165]source/class/class_admincp.php(logincheck)
  [Line: 0113]source/function/function_member.php(DB::fetch_first)

数据库和页面设置相同的字符编码

数据库和页面设置相同的字符编码，统一用utf-8编码，执行查询语句前加上mysql_query("SET NAMES 'UTF8'")