my ($self, $from, $select, $where, $attrs) = @_;
$self->throw_exception ('Nothing to prefetch... how did we get here?!')
- if not @{$attrs->{_prefetch_select}};
+ if not @{$attrs->{_prefetch_selector_range}};
$self->throw_exception ('Complex prefetches are not supported on resultsets with a custom from attribute')
if (ref $from ne 'ARRAY' || ref $from->[0] ne 'HASH' || ref $from->[1] ne 'ARRAY');
delete $outer_attrs->{$_} for qw/where bind rows offset group_by having/;
my $inner_attrs = { %$attrs };
- delete $inner_attrs->{$_} for qw/for collapse _prefetch_select _collapse_order_by select as/;
+ delete $inner_attrs->{$_} for qw/for collapse _prefetch_selector_range _collapse_order_by select as/;
# bring over all non-collapse-induced order_by into the inner query (if any)
# on the outside we substitute any function for its alias
my $outer_select = [ @$select ];
my $inner_select = [];
- for my $i (0 .. ( @$outer_select - @{$outer_attrs->{_prefetch_select}} - 1) ) {
+
+ my ($p_start, $p_end) = @{$outer_attrs->{_prefetch_selector_range}};
+ for my $i (0 .. $p_start - 1, $p_end + 1 .. $#$outer_select) {
my $sel = $outer_select->[$i];
if (ref $sel eq 'HASH' ) {
# also throw in a group_by if restricting to guard against
# cross-join explosions
#
+ my $need_outer_group_by;
while (my $j = shift @$from) {
my $alias = $j->[0]{-alias};
}
elsif ($outer_aliastypes->{restricting}{$alias}) {
push @outer_from, $j;
- $outer_attrs->{group_by} ||= $outer_select unless $j->[0]{-is_single};
+ $need_outer_group_by ||= ! $j->[0]{-is_single};
}
}
# demote the outer_from head
$outer_from[0] = $outer_from[0][0];
+ if ($need_outer_group_by and ! $outer_attrs->{group_by}) {
+
+ my $unprocessed_order_chunks;
+ ($outer_attrs->{group_by}, $unprocessed_order_chunks) = $self->_group_over_selection (
+ \@outer_from, $outer_select, $outer_attrs->{order_by}
+ );
+
+ $self->throw_exception (
+ 'A required group_by clause could not be constructed automatically due to a complex '
+ . 'order_by criteria. Either order_by columns only (no functions) or construct a suitable '
+ . 'group_by by hand'
+ ) if $unprocessed_order_chunks;
+
+ }
+
# This is totally horrific - the $where ends up in both the inner and outer query
# Unfortunately not much can be done until SQLA2 introspection arrives, and even
# then if where conditions apply to the *right* side of the prefetch, you may have
my (@group_by, %group_index);
+ # the logic is: if it is a { func => val } we assume an aggregate,
+ # otherwise if \'...' or \[...] we assume the user knows what is
+ # going on thus group over it
for (@$select) {
if (! ref($_) or ref ($_) ne 'HASH' ) {
push @group_by, $_;