Commit | Line | Data |
01d7143b |
1 | package Data::Query::Renderer::SQL::Slice::GenericSubquery; |
2 | |
3 | use Data::Query::ExprHelpers; |
4 | use Moo::Role; |
5 | |
6 | with 'Data::Query::Renderer::SQL::Slice::SubqueryRemap'; |
7 | |
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8 | sub slice_stability { |
9 | (limit => 'requires', offset => 'requires'); |
10 | } |
11 | |
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12 | sub _render_slice { |
13 | my ($self, $dq) = @_; |
14 | die "Slice's inner is not a Select" |
15 | unless is_Select my $orig_select = $dq->{from}; |
16 | my %remapped = $self->_subquery_remap($orig_select); |
17 | my $first_from = $remapped{inner_body}; |
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18 | # Should we simply strip until we reach a join/alias/etc. here? |
19 | $first_from = $first_from->{from}{from} if is_Having($first_from); |
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20 | $first_from = $first_from->{from} if is_Where($first_from); |
21 | while (is_Join $first_from) { |
22 | $first_from = $first_from->{left}; |
23 | } |
24 | $first_from = $first_from->{from} if is_Alias($first_from); |
25 | my $first_order = $remapped{inside_order}[0]{by}; |
26 | my $count_col = $first_order->{elements}[-1]; |
27 | my $count_alias = 'rownum__emulation'; |
28 | my $count_sel = Select( |
29 | [ Operator({ 'SQL.Naive' => 'apply' }, [ Identifier('COUNT'), Identifier('*') ]) ], |
30 | Where( |
31 | Operator( |
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32 | { 'SQL.Naive' => ($remapped{inside_order}[0]{reverse} ? '>' : '<') }, |
33 | [ |
34 | Identifier($count_alias, $count_col), |
35 | $remapped{outside_order}[0]{by} |
36 | ] |
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37 | ), |
38 | Alias($count_alias, $first_from) |
39 | ) |
40 | ); |
41 | my $count_where = Operator( |
42 | { 'SQL.Naive' => ($dq->{offset} ? 'BETWEEN' : '<') }, |
43 | [ $count_sel, ( |
44 | $dq->{offset} |
45 | ? ( |
46 | $dq->{offset}, |
47 | { |
48 | %{$dq->{limit}}, |
49 | value => $dq->{limit}{value}+$dq->{offset}{value}-1 |
50 | } |
51 | ) |
52 | : ($dq->{limit}) |
53 | ) |
54 | ] |
55 | ); |
56 | return $self->render( |
57 | Select( |
58 | $remapped{outside_select_list}, |
59 | (compose { no warnings 'once'; Order($b->{by}, $b->{reverse}, $a) } |
60 | @{$remapped{outside_order}}, |
61 | Where( |
62 | $count_where, |
63 | Alias( |
64 | $remapped{default_inside_alias}, |
65 | Select( |
66 | $remapped{inside_select_list}, |
67 | $remapped{inner_body}, |
68 | ) |
69 | ) |
70 | ) |
71 | ) |
72 | ) |
73 | ); |
74 | } |
75 | |
76 | 1; |