CREATE TABLE foo (
    id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT,
    this VARCHAR(100) NOT NULL,
    that VARCHAR(100) NOT NULL,
    other VARCHAR(100) NOT NULL,
    PRIMARY KEY(id),
    UNIQUE INDEX(this, that, other)
);

##</code><code>##

sub find_entries
{

	my $sql = "SELECT * " .
			  "FROM foo " . 
			  "WHERE this " .
              "LIKE '%" . $this . "%' " .
              "AND that " .
              "LIKE '%" . $that . "%' " .
              "AND other " .
              "LIKE '%" . $other . "%'";

	my $sth = $dbh->prepare($sql);
	$sth->execute;
    ...
    
    return $entries;

}

##</code><code>##

sub find_entries
{

    my ($this, $that, $other) = @_;
    
	my $sth = $dbh->prepare("SELECT * " .
                            "FROM foo " . 
                            "WHERE this " .
                            "LIKE '%" . "?" . "%' " .
                            "AND that " .
                            "LIKE '%" . "?" . "%' " .
                            "AND other " .
                            "LIKE '%" . "?" . "%'");

    $sth->bind_param(1, $this);
    $sth->bind_param(2, $that);
    $sth->bind_param(3, $other);
    
	$sth->execute();
    
    ...
    
    return $entries;
}

##</code><code>##

*** unhandled exception in callback:
***   DBD::mysql::st bind_param failed: Illegal parameter number