sub runquery {
    my ($dbh, $query, $conds) = @_;
    my @fields = keys %$conds;
    my @values = ();
    if ( @fields ) {
        $query .= " where ";
        $query .= join " and ", map { "$_ $$conds{$_}{op} ?" } @fields;
        @values = map { $$conds{$_}{val} } @fields;
    }
    my $sth = $dbh->prepare( $query );
    $sth->execute( @values );

    my $arref = $sth->fetchrow_arrayref; # (use your own favorite here)
    $sth->finish;
    return $arref;
}

# that sub would be used as follows:

my %qryconditions;  # to be set via GUI or CGI (or not)

# e.g. 
# = ( name =>   { op => '=', val => 'smith' },
#     salary => { op => '>', val => 50000 },
#     department => { op => 'not like', val => 'eng%' } )

# ... connect to DB (with $dbh as object handle), then:

# maybe there's a UI component to choose or create this as well:
my $qstr = "select name, salary, deparment from employees";

my $result_arref = runquery( $dbh, $qstr, \%qryconditions );
for my $row ( @$result_arref ) {
    print join( " ", @$row ), "\n";
}