# User input
my ($name,$middle,$surname) = ('George', 'Washington', 'Clark');

my $query = "
SELECT 
    whatever 
FROM
    mytable 
WHERE 
    name = ? 
    AND middle = ?
    AND surname = ?";
my $sth = $dbh->prepare($query);
$sth->execute>($name, $middle, $surname);
# check if you got any results