我可以在php / postgres pg_escape_string中添加char限制吗？ 如果是这样的话？

I've this php code:

 $reg_number = strtoupper(pg_escape_string($_SESSION['regiter'][2]['serial']));

I need to set $reg_number field to max 10 char adding the limit to this string

Thank you if you provide me the code

EDIT

I need that $reg_number must equal to 10 or under 10 char. (in my postgres db the field is char limit to 10...sorry)

"cutted" results is ok

$reg_number = $_SESSION['regiter'][2]['serial']);
if( strlen($reg_number)>10 ){
    $reg_number = substr($reg_number, 0, 10);
}
$reg_number = pg_escape_string(strtoupper($reg_number));