1 package Data::Query::Renderer::SQL::Slice::FetchFirst;
3 use Data::Query::ExprHelpers;
6 with 'Data::Query::Renderer::SQL::Slice::SubqueryRemap';
8 sub _render_slice_limit {
11 ($dq->{from} ? $self->_render($dq->{from}) : ()),
12 $self->_format_keyword('FETCH FIRST'),
13 sprintf("%i", $dq->{limit}{value}),
14 $self->_format_keyword('ROWS ONLY')
18 sub _slice_type { 'FetchFirst' }
22 unless ($dq->{offset}) {
23 return $self->_render_slice_limit($dq);
25 unless ($dq->{order_is_stable}) {
26 die $self->_slice_type." limit style requires a stable order";
28 die "Slice's inner is not a Select"
29 unless is_Select my $orig_select = $dq->{from};
30 die "Slice's Select not followed by Order but order_is_stable set"
31 unless is_Order $orig_select->{from};
33 my %remapped = $self->_subquery_remap($orig_select);
35 my @inside_select_list = @{$remapped{inside_select_list}};
36 my @outside_select_list = @{$remapped{outside_select_list}};
37 my @inside_order = @{$remapped{inside_order}};
38 my @outside_order = @{$remapped{outside_order}};
39 my $default_inside_alias = $remapped{default_inside_alias};
40 my $inner_body = $remapped{inner_body};
42 my $limit_plus_offset = +{
43 %{$dq->{limit}}, value => $dq->{limit}{value} + $dq->{offset}{value}
46 return $self->_render(
50 \@outside_select_list,
52 Order($b->{by}, $b->{reverse}, $a)
55 Alias($default_inside_alias, $_)
66 ? (grep @{$_->{elements}} == 1,
67 map $_->{by}, @outside_order)
71 Order($b->{by}, !$b->{reverse}, $a)
75 $default_inside_alias,
77 undef, $limit_plus_offset,
81 Order($b->{by}, $b->{reverse}, $a)
82 } @inside_order, $inner_body