credit to *ioaniatr* -- http://stackoverflow.com/a/26661737

my_sql_regcase.php

function my_sql_regcase($str){

    $res = "";

    $chars = str_split($str);
    foreach($chars as $char){
        if(preg_match("/[A-Za-z]/", $char))
            $res .= "[".mb_strtoupper($char, 'UTF-8').mb_strtolower($char, 'UTF-8')."]";
        else
            $res .= $char;
    }

    return $res;
}