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 $self->_format_keyword('ROWS ONLY')
19 (offset => 'requires');
22 sub _slice_type { 'FetchFirst' }
26 unless ($dq->{offset}) {
27 return $self->_render_slice_limit($dq);
29 unless ($dq->{order_is_stable}) {
30 die $self->_slice_type." limit style requires a stable order";
32 die "Slice's inner is not a Select"
33 unless is_Select my $orig_select = $dq->{from};
34 die "Slice's Select not followed by Order but order_is_stable set"
35 unless is_Order $orig_select->{from};
37 my %remapped = $self->_subquery_remap($orig_select);
39 my @inside_select_list = @{$remapped{inside_select_list}};
40 my @outside_select_list = @{$remapped{outside_select_list}};
41 my @inside_order = @{$remapped{inside_order}};
42 my @outside_order = @{$remapped{outside_order}};
43 my $default_inside_alias = $remapped{default_inside_alias};
44 my $inner_body = $remapped{inner_body};
46 my $limit_plus_offset = +{
47 %{$dq->{limit}}, value => $dq->{limit}{value} + $dq->{offset}{value}
50 return $self->_render(
54 \@outside_select_list,
56 Order($b->{by}, $b->{reverse}, $a)
59 Alias($default_inside_alias, $_)
70 ? (grep @{$_->{elements}} == 1,
71 map $_->{by}, @outside_order)
75 Order($b->{by}, !$b->{reverse}, $a)
79 $default_inside_alias,
81 undef, $limit_plus_offset,
85 Order($b->{by}, $b->{reverse}, $a)
86 } @inside_order, $inner_body