1 package DBIx::Class::SQLMaker::LimitDialects;
6 # constants are used not only here, but also in comparison tests
7 sub __rows_bindtype () {
8 +{ sqlt_datatype => 'integer' }
10 sub __offset_bindtype () {
11 +{ sqlt_datatype => 'integer' }
13 sub __total_bindtype () {
14 +{ sqlt_datatype => 'integer' }
19 DBIx::Class::SQLMaker::LimitDialects - SQL::Abstract::Limit-like functionality for DBIx::Class::SQLMaker
23 This module replicates a lot of the functionality originally found in
24 L<SQL::Abstract::Limit>. While simple limits would work as-is, the more
25 complex dialects that require e.g. subqueries could not be reliably
26 implemented without taking full advantage of the metadata locked within
27 L<DBIx::Class::ResultSource> classes. After reimplementation of close to
28 80% of the L<SQL::Abstract::Limit> functionality it was deemed more
29 practical to simply make an independent DBIx::Class-specific limit-dialect
32 =head1 SQL LIMIT DIALECTS
34 Note that the actual implementations listed below never use C<*> literally.
35 Instead proper re-aliasing of selectors and order criteria is done, so that
36 the limit dialect are safe to use on joined resultsets with clashing column
39 Currently the provided dialects are:
43 SELECT ... LIMIT $limit OFFSET $offset
45 Supported by B<PostgreSQL> and B<SQLite>
49 my ( $self, $sql, $rs_attrs, $rows, $offset ) = @_;
50 $sql .= $self->_parse_rs_attrs( $rs_attrs ) . " LIMIT ?";
51 push @{$self->{limit_bind}}, [ $self->__rows_bindtype => $rows ];
54 push @{$self->{limit_bind}}, [ $self->__offset_bindtype => $offset ];
61 SELECT ... LIMIT $offset, $limit
63 Supported by B<MySQL> and any L<SQL::Statement> based DBD
67 my ( $self, $sql, $rs_attrs, $rows, $offset ) = @_;
68 $sql .= $self->_parse_rs_attrs( $rs_attrs ) . " LIMIT ";
71 push @{$self->{limit_bind}}, [ $self->__offset_bindtype => $offset ];
74 push @{$self->{limit_bind}}, [ $self->__rows_bindtype => $rows ];
82 SELECT *, ROW_NUMBER() OVER( ORDER BY ... ) AS RNO__ROW__INDEX FROM (
85 ) WHERE RNO__ROW__INDEX BETWEEN ($offset+1) AND ($limit+$offset)
88 ANSI standard Limit/Offset implementation. Supported by B<DB2> and
93 my ($self, $sql, $rs_attrs, $rows, $offset ) = @_;
95 # get selectors, and scan the order_by (if any)
96 my $sq_attrs = $self->_subqueried_limit_attrs ( $sql, $rs_attrs );
98 # make up an order if none exists
99 my $requested_order = (delete $rs_attrs->{order_by}) || $self->_rno_default_order;
101 # the order binds (if any) will need to go at the end of the entire inner select
102 local $self->{order_bind};
103 my $rno_ord = $self->_order_by ($requested_order);
104 push @{$self->{select_bind}}, @{$self->{order_bind}};
106 # this is the order supplement magic
107 my $mid_sel = $sq_attrs->{selection_outer};
108 if (my $extra_order_sel = $sq_attrs->{order_supplement}) {
109 for my $extra_col (sort
110 { $extra_order_sel->{$a} cmp $extra_order_sel->{$b} }
111 keys %$extra_order_sel
113 $sq_attrs->{selection_inner} .= sprintf (', %s AS %s',
115 $extra_order_sel->{$extra_col},
120 # and this is order re-alias magic
121 for my $map ($sq_attrs->{order_supplement}, $sq_attrs->{outer_renames}) {
122 for my $col (sort { (length $b) <=> (length $a) } keys %{$map||{}} ) {
123 my $re_col = quotemeta ($col);
124 $rno_ord =~ s/$re_col/$map->{$col}/;
128 # whatever is left of the order_by (only where is processed at this point)
129 my $group_having = $self->_parse_rs_attrs($rs_attrs);
131 my $qalias = $self->_quote ($rs_attrs->{alias});
132 my $idx_name = $self->_quote ('rno__row__index');
134 push @{$self->{limit_bind}}, [ $self->__offset_bindtype => $offset + 1], [ $self->__total_bindtype => $offset + $rows ];
138 SELECT $sq_attrs->{selection_outer} FROM (
139 SELECT $mid_sel, ROW_NUMBER() OVER( $rno_ord ) AS $idx_name FROM (
140 SELECT $sq_attrs->{selection_inner} $sq_attrs->{query_leftover}${group_having}
142 ) $qalias WHERE $idx_name >= ? AND $idx_name <= ?
148 # some databases are happy with OVER (), some need OVER (ORDER BY (SELECT (1)) )
149 sub _rno_default_order {
155 SELECT SKIP $offset FIRST $limit * FROM ...
157 Supported by B<Informix>, almost like LimitOffset. According to
158 L<SQL::Abstract::Limit> C<... SKIP $offset LIMIT $limit ...> is also supported.
162 my ($self, $sql, $rs_attrs, $rows, $offset) = @_;
164 $sql =~ s/^ \s* SELECT \s+ //ix
165 or $self->throw_exception("Unrecognizable SELECT: $sql");
167 return sprintf ('SELECT %s%s%s%s',
170 push @{$self->{pre_select_bind}}, [ $self->__offset_bindtype => $offset];
176 push @{$self->{pre_select_bind}}, [ $self->__rows_bindtype => $rows ];
180 $self->_parse_rs_attrs ($rs_attrs),
186 SELECT FIRST $limit SKIP $offset * FROM ...
188 Supported by B<Firebird/Interbase>, reverse of SkipFirst. According to
189 L<SQL::Abstract::Limit> C<... ROWS $limit TO $offset ...> is also supported.
193 my ($self, $sql, $rs_attrs, $rows, $offset) = @_;
195 $sql =~ s/^ \s* SELECT \s+ //ix
196 or $self->throw_exception("Unrecognizable SELECT: $sql");
198 return sprintf ('SELECT %s%s%s%s',
200 push @{$self->{pre_select_bind}}, [ $self->__rows_bindtype => $rows ];
205 push @{$self->{pre_select_bind}}, [ $self->__offset_bindtype => $offset];
211 $self->_parse_rs_attrs ($rs_attrs),
218 Depending on the resultset attributes one of:
221 SELECT *, ROWNUM AS rownum__index FROM (
223 ) WHERE ROWNUM <= ($limit+$offset)
224 ) WHERE rownum__index >= ($offset+1)
229 SELECT *, ROWNUM AS rownum__index FROM (
232 ) WHERE rownum__index BETWEEN ($offset+1) AND ($limit+$offset)
238 ) WHERE ROWNUM <= ($limit+1)
240 Supported by B<Oracle>.
244 my ( $self, $sql, $rs_attrs, $rows, $offset ) = @_;
246 my $sq_attrs = $self->_subqueried_limit_attrs ($sql, $rs_attrs);
248 my $qalias = $self->_quote ($rs_attrs->{alias});
249 my $idx_name = $self->_quote ('rownum__index');
250 my $order_group_having = $self->_parse_rs_attrs($rs_attrs);
253 # if no offset (e.g. first page) - we can skip one of the subqueries
255 push @{$self->{limit_bind}}, [ $self->__rows_bindtype => $rows ];
258 SELECT $sq_attrs->{selection_outer} FROM (
259 SELECT $sq_attrs->{selection_inner} $sq_attrs->{query_leftover}${order_group_having}
260 ) $qalias WHERE ROWNUM <= ?
265 # There are two ways to limit in Oracle, one vastly faster than the other
266 # on large resultsets: https://decipherinfosys.wordpress.com/2007/08/09/paging-and-countstopkey-optimization/
267 # However Oracle is retarded and does not preserve stable ROWNUM() values
268 # when called twice in the same scope. Therefore unless the resultset is
269 # ordered by a unique set of columns, it is not safe to use the faster
270 # method, and the slower BETWEEN query is used instead
272 # FIXME - this is quite expensive, and does not perform caching of any sort
273 # as soon as some of the SQLA-inlining work becomes viable consider adding
274 # some rudimentary caching support
276 $rs_attrs->{order_by}
278 $rs_attrs->{result_source}->schema->storage->_order_by_is_stable(
279 @{$rs_attrs}{qw/from order_by where/}
282 push @{$self->{limit_bind}}, [ $self->__total_bindtype => $offset + $rows ], [ $self->__offset_bindtype => $offset + 1 ];
285 SELECT $sq_attrs->{selection_outer} FROM (
286 SELECT $sq_attrs->{selection_outer}, ROWNUM AS $idx_name FROM (
287 SELECT $sq_attrs->{selection_inner} $sq_attrs->{query_leftover}${order_group_having}
288 ) $qalias WHERE ROWNUM <= ?
289 ) $qalias WHERE $idx_name >= ?
293 push @{$self->{limit_bind}}, [ $self->__offset_bindtype => $offset + 1 ], [ $self->__total_bindtype => $offset + $rows ];
296 SELECT $sq_attrs->{selection_outer} FROM (
297 SELECT $sq_attrs->{selection_outer}, ROWNUM AS $idx_name FROM (
298 SELECT $sq_attrs->{selection_inner} $sq_attrs->{query_leftover}${order_group_having}
300 ) $qalias WHERE $idx_name BETWEEN ? AND ?
305 # used by _Top and _FetchFirst below
306 sub _prep_for_skimming_limit {
307 my ( $self, $sql, $rs_attrs ) = @_;
310 my $sq_attrs = $self->_subqueried_limit_attrs ($sql, $rs_attrs);
312 my $requested_order = delete $rs_attrs->{order_by};
313 $sq_attrs->{order_by_requested} = $self->_order_by ($requested_order);
314 $sq_attrs->{grpby_having} = $self->_parse_rs_attrs ($rs_attrs);
316 # without an offset things are easy
317 if (! $rs_attrs->{offset}) {
318 $sq_attrs->{order_by_inner} = $sq_attrs->{order_by_requested};
321 $sq_attrs->{quoted_rs_alias} = $self->_quote ($rs_attrs->{alias});
323 # localise as we already have all the bind values we need
324 local $self->{order_bind};
326 # make up an order unless supplied or sanity check what we are given
328 if ($sq_attrs->{order_by_requested}) {
329 $self->throw_exception (
330 'Unable to safely perform "skimming type" limit with supplied unstable order criteria'
331 ) unless ($rs_attrs->{result_source}->schema->storage->_order_by_is_stable(
337 $inner_order = $requested_order;
341 { "$rs_attrs->{alias}.$_" }
343 $rs_attrs->{result_source}->_identifying_column_set
345 $self->throw_exception(sprintf(
346 'Unable to auto-construct stable order criteria for "skimming type" limit '
347 . "dialect based on source '%s'", $rs_attrs->{result_source}->name) );
352 $sq_attrs->{order_by_inner} = $self->_order_by ($inner_order);
355 for my $ch ($self->_order_by_chunks ($inner_order)) {
356 $ch = $ch->[0] if ref $ch eq 'ARRAY';
358 ($ch, my ($is_desc, $nulls_pos) ) = $self->_split_order_chunk($ch);
360 # !NOTE! outside chunks come in reverse order ( !$is_desc, !$nulls_pos )
362 ($is_desc ? '-asc' : '-desc') => \$ch,
364 -nulls => ($nulls_pos eq 'FIRST' ? 'LAST' : 'FIRST')
369 $sq_attrs->{order_by_middle} = $self->_order_by (\@out_chunks);
371 # this is the order supplement magic
372 $sq_attrs->{selection_middle} = $sq_attrs->{selection_outer};
373 if (my $extra_order_sel = $sq_attrs->{order_supplement}) {
374 for my $extra_col (sort
375 { $extra_order_sel->{$a} cmp $extra_order_sel->{$b} }
376 keys %$extra_order_sel
378 $sq_attrs->{selection_inner} .= sprintf (', %s AS %s',
380 $extra_order_sel->{$extra_col},
383 $sq_attrs->{selection_middle} .= ', ' . $extra_order_sel->{$extra_col};
386 # Whatever order bindvals there are, they will be realiased and
387 # reselected, and need to show up at end of the initial inner select
388 push @{$self->{select_bind}}, @{$self->{order_bind}};
391 # and this is order re-alias magic
392 for my $map ($sq_attrs->{order_supplement}, $sq_attrs->{outer_renames}) {
393 for my $col (sort { (length $b) <=> (length $a) } keys %{$map||{}}) {
394 my $re_col = quotemeta ($col);
395 $_ =~ s/$re_col/$map->{$col}/
396 for ($sq_attrs->{order_by_middle}, $sq_attrs->{order_by_requested});
408 SELECT TOP $limit FROM (
409 SELECT TOP $limit FROM (
410 SELECT TOP ($limit+$offset) ...
411 ) ORDER BY $reversed_original_order
412 ) ORDER BY $original_order
414 Unreliable Top-based implementation, supported by B<< MSSQL < 2005 >>.
418 Due to its implementation, this limit dialect returns B<incorrect results>
419 when $limit+$offset > total amount of rows in the resultset.
424 my ( $self, $sql, $rs_attrs, $rows, $offset ) = @_;
426 my $lim = $self->_prep_for_skimming_limit($sql, $rs_attrs);
428 $sql = sprintf ('SELECT TOP %u %s %s %s %s',
429 $rows + ($offset||0),
430 $offset ? $lim->{selection_inner} : $lim->{selection_original},
431 $lim->{query_leftover},
432 $lim->{grpby_having},
433 $lim->{order_by_inner},
436 $sql = sprintf ('SELECT TOP %u %s FROM ( %s ) %s %s',
438 $lim->{selection_middle},
440 $lim->{quoted_rs_alias},
441 $lim->{order_by_middle},
444 $sql = sprintf ('SELECT %s FROM ( %s ) %s %s',
445 $lim->{selection_outer},
447 $lim->{quoted_rs_alias},
448 $lim->{order_by_requested},
450 $lim->{order_by_requested} or $lim->{selection_middle} ne $lim->{selection_outer}
463 ) ORDER BY $reversed_original_order
464 FETCH FIRST $limit ROWS ONLY
465 ) ORDER BY $original_order
466 FETCH FIRST $limit ROWS ONLY
469 Unreliable FetchFirst-based implementation, supported by B<< IBM DB2 <= V5R3 >>.
473 Due to its implementation, this limit dialect returns B<incorrect results>
474 when $limit+$offset > total amount of rows in the resultset.
479 my ( $self, $sql, $rs_attrs, $rows, $offset ) = @_;
481 my $lim = $self->_prep_for_skimming_limit($sql, $rs_attrs);
483 $sql = sprintf ('SELECT %s %s %s %s FETCH FIRST %u ROWS ONLY',
484 $offset ? $lim->{selection_inner} : $lim->{selection_original},
485 $lim->{query_leftover},
486 $lim->{grpby_having},
487 $lim->{order_by_inner},
488 $rows + ($offset||0),
491 $sql = sprintf ('SELECT %s FROM ( %s ) %s %s FETCH FIRST %u ROWS ONLY',
492 $lim->{selection_middle},
494 $lim->{quoted_rs_alias},
495 $lim->{order_by_middle},
500 $sql = sprintf ('SELECT %s FROM ( %s ) %s %s',
501 $lim->{selection_outer},
503 $lim->{quoted_rs_alias},
504 $lim->{order_by_requested},
506 $lim->{order_by_requested} or $lim->{selection_middle} ne $lim->{selection_outer}
518 SELECT COUNT(*) FROM $original_table cnt WHERE cnt.id < $original_table.id
519 ) BETWEEN $offset AND ($offset+$rows-1)
521 This is the most evil limit "dialect" (more of a hack) for I<really> stupid
522 databases. It works by ordering the set by some unique column, and calculating
523 the amount of rows that have a less-er value (thus emulating a L</RowNum>-like
524 index). Of course this implies the set can only be ordered by a single unique
527 Also note that this technique can be and often is B<excruciatingly slow>. You
528 may have much better luck using L<DBIx::Class::ResultSet/software_limit>
531 Currently used by B<Sybase ASE>, due to lack of any other option.
535 my ($self, $sql, $rs_attrs, $rows, $offset) = @_;
537 my $main_rsrc = $rs_attrs->{result_source};
539 # Explicitly require an order_by
540 # GenSubQ is slow enough as it is, just emulating things
541 # like in other cases is not wise - make the user work
542 # to shoot their DBA in the foot
543 $self->throw_exception (
544 'Generic Subquery Limit does not work on resultsets without an order. Provide a stable, '
545 . 'main-table-based order criteria.'
546 ) unless $rs_attrs->{order_by};
548 my $usable_order_colinfo = $main_rsrc->schema->storage->_extract_colinfo_of_stable_main_source_order_by_portion(
552 $self->throw_exception(
553 'Generic Subquery Limit can not work with order criteria based on sources other than the main one'
555 ! keys %{$usable_order_colinfo||{}}
558 { $_->{-source_alias} ne $rs_attrs->{alias} }
559 (values %$usable_order_colinfo)
564 ### we need to know the directions after we figured out the above - reextract *again*
565 ### this is eyebleed - trying to get it to work at first
566 my $supplied_order = delete $rs_attrs->{order_by};
568 my @order_bits = do {
569 local $self->{quote_char};
570 local $self->{order_bind};
571 map { ref $_ ? $_->[0] : $_ } $self->_order_by_chunks ($supplied_order)
574 # truncate to what we'll use
575 $#order_bits = ( (keys %$usable_order_colinfo) - 1 );
577 # @order_bits likely will come back quoted (due to how the prefetch
579 # Hence supplement the column_info lookup table with quoted versions
580 if ($self->quote_char) {
581 $usable_order_colinfo->{$self->_quote($_)} = $usable_order_colinfo->{$_}
582 for keys %$usable_order_colinfo;
585 # calculate the condition
586 my $count_tbl_alias = 'rownum__emulation';
587 my $main_alias = $rs_attrs->{alias};
588 my $main_tbl_name = $main_rsrc->name;
590 my (@unqualified_names, @qualified_names, @is_desc, @new_order_by);
592 for my $bit (@order_bits) {
594 ($bit, my ($is_desc, $nulls_pos)) = $self->_split_order_chunk($bit);
596 push @is_desc, $is_desc;
597 push @unqualified_names, $usable_order_colinfo->{$bit}{-colname};
598 push @qualified_names, $usable_order_colinfo->{$bit}{-fq_colname};
600 push @new_order_by, {
601 ($is_desc ? '-desc' : '-asc') => $usable_order_colinfo->{$bit}{-fq_colname},
602 ($nulls_pos ? ( -nulls => lc $nulls_pos ) : ()),
606 my (@where_cond, @skip_colpair_stack);
607 for my $i (0 .. $#order_bits) {
608 my $ci = $usable_order_colinfo->{$order_bits[$i]};
610 my ($subq_col, $main_col) = map { "$_.$ci->{-colname}" } ($count_tbl_alias, $main_alias);
611 my $cur_cond = { $subq_col => { ($is_desc[$i] ? '>' : '<') => { -ident => $main_col } } };
613 push @skip_colpair_stack, [
614 { $main_col => { -ident => $subq_col } },
617 # we can trust the nullability flag because
618 # we already used it during _id_col_set resolution
620 if ($ci->{is_nullable}) {
621 push @{$skip_colpair_stack[-1]}, { $main_col => undef, $subq_col=> undef };
625 ($is_desc[$i] ? $subq_col : $main_col) => { '!=', undef },
626 ($is_desc[$i] ? $main_col : $subq_col) => undef,
629 $subq_col => { '!=', undef },
630 $main_col => { '!=', undef },
636 push @where_cond, { '-and', => [ @skip_colpair_stack[0..$i-1], $cur_cond ] };
639 # reuse the sqlmaker WHERE, this will not be returning binds
640 my $counted_where = do {
641 local $self->{where_bind};
642 $self->where(\@where_cond);
645 # construct the rownum condition by hand
648 $rownum_cond = 'BETWEEN ? AND ?';
649 push @{$self->{limit_bind}},
650 [ $self->__offset_bindtype => $offset ],
651 [ $self->__total_bindtype => $offset + $rows - 1]
655 $rownum_cond = '< ?';
656 push @{$self->{limit_bind}},
657 [ $self->__rows_bindtype => $rows ]
661 # and what we will order by inside
662 my $inner_order_sql = do {
663 local $self->{order_bind};
665 my $s = $self->_order_by (\@new_order_by);
667 $self->throw_exception('Inner gensubq order may not contain binds... something went wrong')
668 if @{$self->{order_bind}};
673 ### resume originally scheduled programming
677 # we need to supply the order for the supplements to be properly calculated
678 my $sq_attrs = $self->_subqueried_limit_attrs (
679 $sql, { %$rs_attrs, order_by => \@new_order_by }
682 my $in_sel = $sq_attrs->{selection_inner};
684 # add the order supplement (if any) as this is what will be used for the outer WHERE
685 $in_sel .= ", $_" for sort keys %{$sq_attrs->{order_supplement}};
687 my $group_having_sql = $self->_parse_rs_attrs($rs_attrs);
691 SELECT $sq_attrs->{selection_outer}
693 SELECT $in_sel $sq_attrs->{query_leftover}${group_having_sql}
695 WHERE ( SELECT COUNT(*) FROM %s %s $counted_where ) $rownum_cond
697 ", map { $self->_quote ($_) } (
705 # !!! THIS IS ALSO HORRIFIC !!! /me ashamed
707 # Generates inner/outer select lists for various limit dialects
708 # which result in one or more subqueries (e.g. RNO, Top, RowNum)
709 # Any non-main-table columns need to have their table qualifier
710 # turned into a column alias (otherwise names in subqueries clash
711 # and/or lose their source table)
713 # Returns mangled proto-sql, inner/outer strings of SQL QUOTED selectors
714 # with aliases (to be used in whatever select statement), and an alias
715 # index hashref of QUOTED SEL => QUOTED ALIAS pairs (to maybe be used
716 # for string-subst higher up).
717 # If an order_by is supplied, the inner select needs to bring out columns
718 # used in implicit (non-selected) orders, and the order condition itself
719 # needs to be realiased to the proper names in the outer query. Thus we
720 # also return a hashref (order doesn't matter) of QUOTED EXTRA-SEL =>
721 # QUOTED ALIAS pairs, which is a list of extra selectors that do *not*
722 # exist in the original select list
723 sub _subqueried_limit_attrs {
724 my ($self, $proto_sql, $rs_attrs) = @_;
726 $self->throw_exception(
727 'Limit dialect implementation usable only in the context of DBIC (missing $rs_attrs)'
728 ) unless ref ($rs_attrs) eq 'HASH';
730 # mangle the input sql as we will be replacing the selector entirely
732 $rs_attrs->{_selector_sql}
734 $proto_sql =~ s/^ \s* SELECT \s* \Q$rs_attrs->{_selector_sql}//ix
736 $self->throw_exception("Unrecognizable SELECT: $proto_sql");
739 my ($re_sep, $re_alias) = map { quotemeta $_ } ( $self->{name_sep}, $rs_attrs->{alias} );
741 # correlate select and as, build selection index
742 my (@sel, $in_sel_index);
743 for my $i (0 .. $#{$rs_attrs->{select}}) {
745 my $s = $rs_attrs->{select}[$i];
746 my $sql_alias = (ref $s) eq 'HASH' ? $s->{-as} : undef;
748 # we throw away the @bind here deliberately
749 my ($sql_sel) = $self->_recurse_fields ($s);
755 local $self->{quote_char};
756 ($self->_recurse_fields ($s))[0]; # ignore binds again
763 $self->throw_exception("Select argument $i ($s) without corresponding 'as'")
767 # anything with a placeholder in it needs re-selection
768 $in_sel_index->{$sql_sel}++ unless $sql_sel =~ / (?: ^ | \W ) \? (?: \W | $ ) /x;
770 $in_sel_index->{$self->_quote ($sql_alias)}++ if $sql_alias;
772 # record unqualified versions too, so we do not have
773 # to reselect the same column twice (in qualified and
775 if (! ref $s && $sql_sel =~ / $re_sep (.+) $/x) {
776 $in_sel_index->{$1}++;
781 # re-alias and remove any name separators from aliases,
782 # unless we are dealing with the current source alias
783 # (which will transcend the subqueries as it is necessary
784 # for possible further chaining)
785 # same for anything we do not recognize
787 for my $node (@sel) {
788 push @{$sel->{original}}, $node->{sql};
791 ! $in_sel_index->{$node->{sql}}
793 $node->{as} =~ / (?<! ^ $re_alias ) \. /x
795 $node->{unquoted_sql} =~ / (?<! ^ $re_alias ) $re_sep /x
797 $node->{as} = $self->_unqualify_colname($node->{as});
798 my $quoted_as = $self->_quote($node->{as});
799 push @{$sel->{inner}}, sprintf '%s AS %s', $node->{sql}, $quoted_as;
800 push @{$sel->{outer}}, $quoted_as;
801 $renamed->{$node->{sql}} = $quoted_as;
804 push @{$sel->{inner}}, $node->{sql};
805 push @{$sel->{outer}}, $self->_quote (ref $node->{arg} ? $node->{as} : $node->{arg});
809 # see if the order gives us anything
811 for my $chunk ($self->_order_by_chunks ($rs_attrs->{order_by})) {
813 $chunk = $chunk->[0] if (ref $chunk) eq 'ARRAY';
814 ($chunk) = $self->_split_order_chunk($chunk);
816 next if $in_sel_index->{$chunk};
818 $extra_order_sel->{$chunk} ||= $self->_quote (
819 'ORDER__BY__' . sprintf '%03d', scalar keys %{$extra_order_sel||{}}
824 query_leftover => $proto_sql,
825 (map {( "selection_$_" => join (', ', @{$sel->{$_}} ) )} keys %$sel ),
826 outer_renames => $renamed,
827 order_supplement => $extra_order_sel,
831 sub _unqualify_colname {
832 my ($self, $fqcn) = @_;
833 $fqcn =~ s/ \. /__/xg;
837 =head1 FURTHER QUESTIONS?
839 Check the list of L<additional DBIC resources|DBIx::Class/GETTING HELP/SUPPORT>.
841 =head1 COPYRIGHT AND LICENSE
843 This module is free software L<copyright|DBIx::Class/COPYRIGHT AND LICENSE>
844 by the L<DBIx::Class (DBIC) authors|DBIx::Class/AUTHORS>. You can
845 redistribute it and/or modify it under the same terms as the
846 L<DBIx::Class library|DBIx::Class/COPYRIGHT AND LICENSE>.