php对字符串进行SQL注入过滤
解决方法：
function sqlfilter($string){
$string_old = $string;
$string = str_ireplace("\\","/",$string);
$string = str_ireplace("\"","/",$string);
$string = str_ireplace("'","/",$string);
$string = str_ireplace("*","/",$string);
$string = str_ireplace("%5C","/",$string);
$string = str_ireplace("%22","/",$string);
$string = str_ireplace("%27","/",$string);
$string = str_ireplace("%2A","/",$string);
$string = str_ireplace("~","/",$string);
$string = str_ireplace("select", "\sel\ect", $string);
$string = str_ireplace("insert", "\ins\ert", $string);
$string = str_ireplace("update", "\up\date", $string);
$string = str_ireplace("delete", "\de\lete", $string);
$string = str_ireplace("union", "\un\ion", $string);
$string = str_ireplace("into", "\in\to", $string);
$string = str_ireplace("load_file", "\load\_\file", $string);
$string = str_ireplace("outfile", "\out\file", $string);
$string = str_ireplace("sleep", "\sle\ep", $string);
$string = strip_tags($string);
if($string_old!=$string){
$string='';
}
$string = trim($string);
return $string;
}