您必须首先通过PHP清理输入.

You must first sanitize your inputs via PHP.

$id = 'asdf';
if(is_numeric($id)){
    $query("SELECT 1 FROM myTable WHERE id = $id");
}else{
    die("ID is not numeric");
}

或者您可以这样做:

    SELECT 1 FROM myTable WHERE id = 'asdf' AND 'asdf' REGEXP '^-?[0-9]+$'

这将导致正则表达式= false，导致不返回任何行.

This would cause the regex to = false, causing no rows to return.