my $stmt = new SQL::Fragment("SELECT *, PRICE+? FROM ITEMS", $fees);

  my @conds = ();
  push(@conds, new SQL::Fragment("color = ?", "blue"));
  push(@conds, [ "size = ?", "XXL" ]); # can also just use array refs

  if (@conds) {
    $stmt->append(" WHERE ")->append_join(" AND ", @conds);
  }

  my ($sql, @params) = $stmt->sql_and_params;

##</code><code>##

sub append - append another SQL Fragment to $self
sub append_join - append a join-ed list of SQL Fragments to $self
sub append_join_parens - do the equivalent of:

  join( $sep, map { "($_)" } @list )

For instance, this is useful to ensure each condition is in it's own set of parens.

##</code><code>##

 sub append_join_parens {
   my $self = shift;
   $self->append_join_map( sub {
        [ "(".$_->sql.")", $_->params ]
   });
   $self;
 }