Assuming you are talking about "Query by Example" another standard way, that has the main advantage of being very readable and easy to maintain is quite the following. But it only works good, if it is also O.K. to work with the LIKE statement:

# I assume the database handler $dbh is already initialized

my $sth = $dbh->prepare("
   SELECT * FROM table 
   WHERE field1 LIKE ?
   AND   field2 LIKE ?
   AND   field3 LIKE ?
   AND   field4 LIKE ?
   AND   field5 LIKE ?
");

for ($field1, $field2, $field3, $field4, $field5) {
   $_ = "" unless defined $_;
   $_ .= "%";
}

$dbh->execute($field1, $field2, $field3, $field4, $field5);

# But please choose better names than $fieldX :-)
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Greetings,
Janek