X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=scpubgit%2FQ-Branch.git;a=blobdiff_plain;f=lib%2FSQL%2FAbstract%2FExtraClauses.pm;h=e1029bcd247bad056d5a0c4e1b88dc434f808b43;hp=ae1ded51419cdc7fd27e4d8061278f1772c8425a;hb=e376aa8053a377ca85e9a16205132b30436b2ce5;hpb=2b0b3d43c5d042c60b97b0d84bfc85cfec9d82ac diff --git a/lib/SQL/Abstract/ExtraClauses.pm b/lib/SQL/Abstract/ExtraClauses.pm index ae1ded5..e1029bc 100644 --- a/lib/SQL/Abstract/ExtraClauses.pm +++ b/lib/SQL/Abstract/ExtraClauses.pm @@ -1,17 +1,45 @@ package SQL::Abstract::ExtraClauses; -use strict; -use warnings; -use if $] < '5.010', 'MRO::Compat'; -use mro 'c3'; -use base qw(SQL::Abstract::Clauses); - -BEGIN { *puke = \&SQL::Abstract::puke } - -sub register_defaults { - my $self = shift; - $self->next::method(@_); - my @clauses = $self->clauses_of('select'); +use Moo; + +has sqla => ( + is => 'ro', init_arg => undef, + handles => [ qw( + expand_expr render_aqt join_query_parts + ) ], +); + +sub cb { + my ($self, $method, @args) = @_; + return sub { + local $self->{sqla} = shift; + $self->$method(@args, @_) + }; +} + +sub register { + my ($self, @pairs) = @_; + my $sqla = $self->sqla; + while (my ($method, $cases) = splice(@pairs, 0, 2)) { + my @cases = @$cases; + while (my ($name, $case) = splice(@cases, 0, 2)) { + $sqla->$method($name, $self->cb($case)); + } + } + return $self; +} + +sub apply_to { + my ($self, $sqla) = @_; + $self = $self->new unless ref($self); + local $self->{sqla} = $sqla; + $self->register_extensions($sqla); +} + +sub register_extensions { + my ($self, $sqla) = @_; + + my @clauses = $sqla->clauses_of('select'); my @before_setop; CLAUSE: foreach my $idx (0..$#clauses) { if ($clauses[$idx] eq 'order_by') { @@ -20,112 +48,106 @@ sub register_defaults { last CLAUSE; } } + die "Huh?" unless @before_setop; - $self->clauses_of(select => @clauses); - $self->clause_expanders( - 'select.group_by', sub { - $_[0]->_expand_maybe_list_expr($_[1], -ident) - }, - 'select.having', 'expand_expr', - ); - foreach my $thing (qw(join from_list)) { - $self->expander($thing => "_expand_${thing}") - ->renderer($thing => "_render_${thing}") - } - $self->op_expander(as => '_expand_op_as'); - $self->expander(as => '_expand_op_as'); - $self->renderer(as => '_render_as'); + $sqla->clauses_of(select => @clauses); - $self->clauses_of(update => sub { + $sqla->clauses_of(update => sub { my ($self, @clauses) = @_; splice(@clauses, 2, 0, 'from'); @clauses; }); - $self->clauses_of(delete => sub { + $sqla->clauses_of(delete => sub { my ($self, @clauses) = @_; splice(@clauses, 1, 0, 'using'); @clauses; }); - $self->clause_expanders( - 'update.from' => '_expand_select_clause_from', - 'delete.using' => sub { - +(using => $_[0]->_expand_from_list(undef, $_[1])); - }, - 'insert.rowvalues' => sub { - +(from => $_[0]->expand_expr({ -values => $_[1] })); - }, - 'insert.select' => sub { - +(from => $_[0]->expand_expr({ -select => $_[1] })); - }, + $self->register( + (map +( + "${_}er" => [ + do { + my $x = $_; + (map +($_ => "_${x}_${_}"), qw(join from_list alias)) + } + ] + ), qw(expand render)), + binop_expander => [ as => '_expand_op_as' ], + renderer => [ as => '_render_as' ], + expander => [ cast => '_expand_cast' ], + clause_expanders => [ + "select.from", '_expand_from_list', + 'select.group_by' + => sub { $_[0]->expand_expr({ -list => $_[2] }, -ident) }, + 'select.having' + => sub { $_[0]->expand_expr($_[2]) }, + 'update.from' => '_expand_from_list', + "update.target", '_expand_update_clause_target', + "update.update", '_expand_update_clause_target', + 'delete.using' => '_expand_from_list', + 'insert.rowvalues' => sub { + +(from => $_[0]->expand_expr({ -values => $_[2] })); + }, + 'insert.select' => sub { + +(from => $_[0]->expand_expr({ -select => $_[2] })); + }, + ], ); # set ops - { - my $orig = $self->expander('select'); - $self->expander(select => sub { - my $self = shift; - my $exp = $self->$orig(@_); - return $exp unless my $setop = (my $sel = $exp->{-select})->{setop}; - if (my @keys = grep $sel->{$_}, @before_setop) { - my %inner; @inner{@keys} = delete @{$sel}{@keys}; - unshift @{(values(%$setop))[0]{queries}}, - { -select => \%inner }; - } - return $exp; - }); - } - - $self->clause_expander('select.union' => sub { - +(setop => $_[0]->expand_expr({ - -union => { - queries => (ref($_[1]) eq 'ARRAY' ? $_[1] : [ $_[1] ]), - } - })); - }); - $self->clause_expander('select.union_all' => sub { - +(setop => $_[0]->expand_expr({ - -union => { - type => 'all', - queries => (ref($_[1]) eq 'ARRAY' ? $_[1] : [ $_[1] ]), - } - })); - }); - $self->expander(union => sub { - my ($self, undef, $args) = @_; - +{ -union => { - %$args, - queries => [ map $self->expand_expr($_), @{$args->{queries}} ], - } }; + $sqla->wrap_expander(select => sub { + $self->cb('_expand_select', $_[0], \@before_setop); }); - $self->clause_renderer('select.setop' => sub { - my ($self, $setop) = @_; - $self->render_aqt($setop); - }); + $self->register( + clause_renderer => [ + 'select.setop' => sub { $_[0]->render_aqt($_[2]) } + ], + expander => [ + map +($_ => '_expand_setop', "${_}_all" => '_expand_setop'), qw(union intersect except) ], + renderer => [ map +($_ => '_render_setop'), qw(union intersect except) ], + ); + + my $setop_expander = $self->cb('_expand_clause_setop'); - $self->renderer(union => sub { - my ($self, $args) = @_; - $self->join_clauses( - ' '.$self->format_keyword(join '_', 'union', ($args->{type}||())).' ', - map [ $self->render_aqt($_) ], @{$args->{queries}} + $sqla->clause_expanders( + map +($_ => $setop_expander), + map "select.${_}", + map +($_, "${_}_all", "${_}_distinct"), + qw(union intersect except) + ); + + foreach my $stmt (qw(select insert update delete)) { + $sqla->clauses_of($stmt => 'with', $sqla->clauses_of($stmt)); + $self->register( + clause_expanders => [ + "${stmt}.with" => '_expand_with', + "${stmt}.with_recursive" => '_expand_with', + ], + clause_renderer => [ "${stmt}.with" => '_render_with' ], ); - }); + } - return $self; + return $sqla; } -sub format_keyword { $_[0]->_sqlcase(join ' ', split '_', $_[1]) } - -sub _expand_select_clause_from { - my ($self, $from) = @_; - +(from => $self->_expand_from_list(undef, $from)); +sub _expand_select { + my ($self, $orig, $before_setop, @args) = @_; + my $exp = $self->sqla->$orig(@args); + return $exp unless my $setop = (my $sel = $exp->{-select})->{setop}; + if (my @keys = grep $sel->{$_}, @$before_setop) { + my %inner; @inner{@keys} = delete @{$sel}{@keys}; + unshift @{(values(%$setop))[0]{queries}}, + { -select => \%inner }; + } + return $exp; } sub _expand_from_list { my ($self, undef, $args) = @_; if (ref($args) eq 'HASH') { + return $args if $args->{-from_list}; return { -from_list => [ $self->expand_expr($args) ] }; } my @list; @@ -146,6 +168,7 @@ sub _expand_from_list { } push @list, $aqt; } + return $list[0] if @list == 1; return { -from_list => \@list }; } @@ -154,75 +177,783 @@ sub _expand_join { my %proto = ( ref($args) eq 'HASH' ? %$args - : (to => $args->[0], @{$args}[1..$#$args]) + : (to => @$args) ); if (my $as = delete $proto{as}) { - $proto{to} = { -as => [ $proto{to}, ref($as) eq 'ARRAY' ? @$as : $as ] }; + $proto{to} = $self->expand_expr( + { -as => [ { -from_list => $proto{to} }, $as ] } + ); } if (defined($proto{using}) and ref(my $using = $proto{using}) ne 'HASH') { - $proto{using} = { -row => [ + $proto{using} = [ map [ $self->expand_expr($_, -ident) ], ref($using) eq 'ARRAY' ? @$using: $using - ] }; + ]; } - my %ret = map +($_ => $self->expand_expr($proto{$_}, -ident)), - sort keys %proto; + my %ret = ( + type => delete $proto{type}, + to => $self->expand_expr({ -from_list => delete $proto{to} }, -ident) + ); + %ret = (%ret, + map +($_ => $self->expand_expr($proto{$_}, -ident)), + sort keys %proto + ); return +{ -join => \%ret }; } sub _render_from_list { - my ($self, $list) = @_; - return $self->join_clauses(', ', map [ $self->render_aqt($_) ], @$list); + my ($self, undef, $list) = @_; + return $self->join_query_parts(', ', @$list); } sub _render_join { - my ($self, $args) = @_; + my ($self, undef, $args) = @_; my @parts = ( - [ $self->render_aqt($args->{from}) ], - [ $self->format_keyword(join '_', ($args->{type}||()), 'join') ], - [ $self->render_aqt( - map +($_->{-ident} || $_->{-as} ? $_ : { -row => [ $_ ] }), $args->{to} - ) ], + $args->{from}, + { -keyword => join '_', ($args->{type}||()), 'join' }, + (map +($_->{-ident} || $_->{-as} + ? $_ + : ('(', $self->render_aqt($_, 1), ')')), + map +(@{$_->{-from_list}||[]} == 1 ? $_->{-from_list}[0] : $_), + $args->{to} + ), ($args->{on} ? ( - [ $self->format_keyword('on') ], - [ $self->render_aqt($args->{on}) ], + { -keyword => 'on' }, + $args->{on}, ) : ()), ($args->{using} ? ( - [ $self->format_keyword('using') ], - [ $self->render_aqt($args->{using}) ], + { -keyword => 'using' }, + '(', $args->{using}, ')', ) : ()), ); - return $self->join_clauses(' ', @parts); + return $self->join_query_parts(' ', @parts); } sub _expand_op_as { my ($self, undef, $vv, $k) = @_; - my @as = map $self->expand_expr($_, -ident), - (defined($k) ? ($k) : ()), ref($vv) eq 'ARRAY' ? @$vv : $vv; - return { -as => \@as }; + my @vv = (ref($vv) eq 'ARRAY' ? @$vv : $vv); + my $ik = $self->expand_expr($k, -ident); + return +{ -as => [ $ik, $self->expand_expr($vv[0], -ident) ] } + if @vv == 1 and ref($vv[0]) eq 'HASH'; + + my @as = map $self->expand_expr($_, -ident), @vv; + return { -as => [ $ik, $self->expand_expr({ -alias => \@as }) ] }; } sub _render_as { - my ($self, $args) = @_; - my ($thing, $as, @cols) = @$args; - return $self->join_clauses( + my ($self, undef, $args) = @_; + my ($thing, $alias) = @$args; + return $self->join_query_parts( ' ', - [ $self->render_aqt($thing) ], - [ $self->format_keyword('as') ], - (@cols - ? [ $self->join_clauses('', - [ $self->render_aqt($as) ], - [ '(' ], - [ $self->join_clauses( - ', ', - map [ $self->render_aqt($_) ], @cols - ) ], - [ ')' ], - ) ] - : [ $self->render_aqt($as) ] - ), + $thing, + { -keyword => 'as' }, + $alias, + ); +} + +sub _render_alias { + my ($self, undef, $args) = @_; + my ($as, @cols) = @$args; + return (@cols + ? $self->join_query_parts('', + $as, + '(', + $self->join_query_parts( + ', ', + @cols + ), + ')', + ) + : $self->render_aqt($as) + ); +} + +sub _expand_update_clause_target { + my ($self, undef, $target) = @_; + +(target => $self->_expand_from_list(undef, $target)); +} + +sub _expand_cast { + my ($self, undef, $thing) = @_; + return { -func => [ cast => $thing ] } if ref($thing) eq 'HASH'; + my ($cast, $to) = @{$thing}; + +{ -func => [ cast => { -as => [ + $self->expand_expr($cast), + $self->expand_expr($to, -ident), + ] } ] }; +} + +sub _expand_alias { + my ($self, undef, $args) = @_; + if (ref($args) eq 'HASH' and my $alias = $args->{-alias}) { + $args = $alias; + } + my @parts = map $self->expand_expr($_, -ident), + ref($args) eq 'ARRAY' ? @{$args} : $args; + return $parts[0] if @parts == 1; + return { -alias => \@parts }; +} + +sub _expand_with { + my ($self, $name, $with) = @_; + my (undef, $type) = split '_', $name; + if (ref($with) eq 'HASH') { + return +{ + %$with, + queries => [ + map +[ + $self->expand_expr({ -alias => $_->[0] }, -ident), + $self->expand_expr($_->[1]), + ], @{$with->{queries}} + ] + } + } + my @with = @$with; + my @exp; + while (my ($alias, $query) = splice @with, 0, 2) { + push @exp, [ + $self->expand_expr({ -alias => $alias }, -ident), + $self->expand_expr($query) + ]; + } + return +(with => { ($type ? (type => $type) : ()), queries => \@exp }); +} + +sub _render_with { + my ($self, undef, $with) = @_; + my $q_part = $self->join_query_parts(', ', + map { + my ($alias, $query) = @$_; + $self->join_query_parts(' ', + $alias, + { -keyword => 'as' }, + $query, + ) + } @{$with->{queries}} + ); + return $self->join_query_parts(' ', + { -keyword => join '_', 'with', ($with->{type}||'') }, + $q_part, ); } +sub _expand_setop { + my ($self, $setop, $args) = @_; + my $is_all = $setop =~ s/_all$//; + +{ "-${setop}" => { + ($is_all ? (type => 'all') : ()), + (ref($args) eq 'ARRAY' + ? (queries => [ map $self->expand_expr($_), @$args ]) + : ( + %$args, + queries => [ map $self->expand_expr($_), @{$args->{queries}} ] + ) + ), + } }; +} + +sub _render_setop { + my ($self, $setop, $args) = @_; + $self->join_query_parts( + { -keyword => ' '.join('_', $setop, ($args->{type}||())).' ' }, + @{$args->{queries}} + ); +} + +sub _expand_clause_setop { + my ($self, $setop, $args) = @_; + my ($op, $type) = split '_', $setop; + +(setop => $self->expand_expr({ + "-${op}" => { + ($type ? (type => $type) : ()), + queries => (ref($args) eq 'ARRAY' ? $args : [ $args ]) + } + })); +} + 1; + +__END__ + +=head1 NAME + +SQL::Abstract::ExtraClauses - new/experimental additions to L + +=head1 SYNOPSIS + + my $sqla = SQL::Abstract->new; + SQL::Abstract::ExtraClauses->apply_to($sqla); + +=head1 WARNING + +This module is basically a nursery for things that seem like a good idea +to live in until we figure out if we were right about that. + +=head1 METHODS + +=head2 apply_to + +Applies the plugin to an L object. + +=head2 register_extensions + +Registers the extensions described below + +=head2 cb + +For plugin authors, creates a callback to call a method on the plugin. + +=head2 register + +For plugin authors, registers callbacks more easily. + +=head2 sqla + +Available only during plugin callback executions, contains the currently +active L object. + +=head1 NODE TYPES + +=head2 alias + +Represents a table alias. Expands name and column names with ident as default. + + # expr + { -alias => [ 't', 'x', 'y', 'z' ] } + + # aqt + { -alias => [ + { -ident => [ 't' ] }, { -ident => [ 'x' ] }, + { -ident => [ 'y' ] }, { -ident => [ 'z' ] }, + ] } + + # query + t(x, y, z) + [] + +=head2 as + +Represents an sql AS. LHS is expanded with ident as default, RHS is treated +as a list of arguments for the alias node. + + # expr + { foo => { -as => 'bar' } } + + # aqt + { -as => [ { -ident => [ 'foo' ] }, { -ident => [ 'bar' ] } ] } + + # query + foo AS bar + [] + + # expr + { -as => [ { -select => { _ => 'blah' } }, 't', 'blah' ] } + + # aqt + { -as => [ + { -select => + { select => { -op => [ ',', { -ident => [ 'blah' ] } ] } } + }, + { -alias => [ { -ident => [ 't' ] }, { -ident => [ 'blah' ] } ] }, + ] } + + # query + (SELECT blah) AS t(blah) + [] + +=head2 cast + + # expr + { -cast => [ { -ident => 'birthday' }, 'date' ] } + + # aqt + { -func => [ + 'cast', { + -as => [ { -ident => [ 'birthday' ] }, { -ident => [ 'date' ] } ] + }, + ] } + + # query + CAST(birthday AS date) + [] + +=head2 join + +If given an arrayref, pretends it was given a hashref with the first +element of the arrayref as the value for 'to' and the remaining pairs copied. + +Given a hashref, the 'as' key is if presented expanded to wrap the 'to'. + +If present the 'using' key is expanded as a list of idents. + +Known keys are: 'from' (the left hand side), 'type' ('left', 'right', or +nothing), 'to' (the right hand side), 'on' and 'using'. + + # expr + { -join => { + from => 'lft', + on => { 'lft.bloo' => { '>' => 'rgt.blee' } }, + to => 'rgt', + type => 'left', + } } + + # aqt + { -join => { + from => { -ident => [ 'lft' ] }, + on => { -op => [ + '>', { -ident => [ 'lft', 'bloo' ] }, + { -ident => [ 'rgt', 'blee' ] }, + ] }, + to => { -ident => [ 'rgt' ] }, + type => 'left', + } } + + # query + lft LEFT JOIN rgt ON lft.bloo > rgt.blee + [] + +=head2 from_list + +List of components of the FROM clause; -foo type elements indicate a pair +with the next element; this is easiest if I show you: + + # expr + { -from_list => [ + 't1', -as => 'table_one', -join => + [ 't2', 'on', { 'table_one.x' => 't2.x' } ], + ] } + + # aqt + { -join => { + from => + { + -as => [ { -ident => [ 't1' ] }, { -ident => [ 'table_one' ] } ] + }, + on => { -op => [ + '=', { -ident => [ 'table_one', 'x' ] }, + { -ident => [ 't2', 'x' ] }, + ] }, + to => { -ident => [ 't2' ] }, + type => undef, + } } + + # query + t1 AS table_one JOIN t2 ON table_one.x = t2.x + [] + +Or with using: + + # expr + { -from_list => + [ 't1', -as => 'table_one', -join => [ 't2', 'using', [ 'x' ] ] ] + } + + # aqt + { -join => { + from => + { + -as => [ { -ident => [ 't1' ] }, { -ident => [ 'table_one' ] } ] + }, + to => { -ident => [ 't2' ] }, + type => undef, + using => + { -op => [ 'or', { -op => [ 'or', { -ident => [ 'x' ] } ] } ] }, + } } + + # query + t1 AS table_one JOIN t2 USING ( x ) + [] + +With oddities: + + # expr + { -from_list => [ + 'x', -join => + [ [ 'y', -join => [ 'z', 'type', 'left' ] ], 'type', 'left' ], + ] } + + # aqt + { -join => { + from => { -ident => [ 'x' ] }, + to => { -join => { + from => { -ident => [ 'y' ] }, + to => { -ident => [ 'z' ] }, + type => 'left', + } }, + type => 'left', + } } + + # query + x LEFT JOIN ( y LEFT JOIN z ) + [] + +=head2 setops + +Expanders are provided for union, union_all, intersect, intersect_all, +except and except_all, and each takes an arrayref of queries: + + # expr + { -union => [ + { -select => { _ => { -value => 1 } } }, + { -select => { _ => { -value => 2 } } }, + ] } + + # aqt + { -union => { queries => [ + { -select => + { select => { -op => [ ',', { -bind => [ undef, 1 ] } ] } } + }, + { -select => + { select => { -op => [ ',', { -bind => [ undef, 2 ] } ] } } + }, + ] } } + + # query + (SELECT ?) UNION (SELECT ?) + [ 1, 2 ] + + # expr + { -union_all => [ + { -select => { _ => { -value => 1 } } }, + { -select => { _ => { -value => 2 } } }, + { -select => { _ => { -value => 1 } } }, + ] } + + # aqt + { -union => { + queries => [ + { -select => + { select => { -op => [ ',', { -bind => [ undef, 1 ] } ] } } + }, + { -select => + { select => { -op => [ ',', { -bind => [ undef, 2 ] } ] } } + }, + { -select => + { select => { -op => [ ',', { -bind => [ undef, 1 ] } ] } } + }, + ], + type => 'all', + } } + + # query + (SELECT ?) UNION ALL (SELECT ?) UNION ALL (SELECT ?) + [ 1, 2, 1 ] + +=head1 STATEMENT EXTENSIONS + +=head2 group by clause for select + +Expanded as a list with an ident default: + + # expr + { -select => { group_by => [ 'foo', 'bar' ] } } + + # aqt + { -select => { group_by => + { + -op => [ ',', { -ident => [ 'foo' ] }, { -ident => [ 'bar' ] } ] + } + } } + + # query + GROUP BY foo, bar + [] + +=head2 having clause for select + +Basic expr, just like where, given having is pretty much post-group-by +where clause: + + # expr + { -select => + { having => { '>' => [ { -count => { -ident => 'foo' } }, 3 ] } } + } + + # aqt + { -select => { having => { -op => [ + '>', { -func => [ 'count', { -ident => [ 'foo' ] } ] }, + { -bind => [ undef, 3 ] }, + ] } } } + + # query + HAVING COUNT(foo) > ? + [ 3 ] + +=head2 setop clauses + +If a select query contains a clause matching any of the setop node types, +clauses that appear before the setop would in the resulting query are +gathered together and moved into an inner select node: + + # expr + { -select => { + _ => '*', + from => 'foo', + order_by => 'baz', + union => + { + -select => { _ => '*', from => 'bar', where => { thing => 1 } } + }, + where => { thing => 1 }, + } } + + # aqt + { -select => { + order_by => { -op => [ ',', { -ident => [ 'baz' ] } ] }, + setop => { -union => { queries => [ + { -select => { + from => { -ident => [ 'foo' ] }, + select => { -op => [ ',', { -ident => [ '*' ] } ] }, + where => { -op => [ + '=', { -ident => [ 'thing' ] }, + { -bind => [ 'thing', 1 ] }, + ] }, + } }, ] }, + { -select => { + from => { -ident => [ 'bar' ] }, + select => { -op => [ ',', { -ident => [ '*' ] } ] }, + where => { -op => [ + '=', { -ident => [ 'thing' ] }, + { -bind => [ 'thing', 1 ] }, + } }, + ] } }, + } } + + # query + (SELECT * FROM foo WHERE thing = ?) UNION ( + SELECT * FROM bar WHERE thing = ? + ) + ORDER BY baz + [ 1, 1 ] + +=head2 update from clause + +Some databases allow an additional FROM clause to reference other tables +for the data to update; this clause is expanded as a normal from list, check +your database for what is and isn't allowed in practice. + + # expr + { -update => { + _ => 'employees', + from => 'accounts', + set => { sales_count => { sales_count => { '+' => \1 } } }, + where => { + 'accounts.name' => { '=' => \"'Acme Corporation'" }, + 'employees.id' => { -ident => 'accounts.sales_person' }, + }, + } } + + # aqt + { -update => { + from => { -ident => [ 'accounts' ] }, + set => { -op => [ + ',', { -op => [ + '=', { -ident => [ 'sales_count' ] }, { -op => [ + '+', { -ident => [ 'sales_count' ] }, + { -literal => [ 1 ] }, + ] }, + ] }, + ] }, + target => { -ident => [ 'employees' ] }, + where => { -op => [ + 'and', { -op => [ + '=', { -ident => [ 'accounts', 'name' ] }, + { -literal => [ "'Acme Corporation'" ] }, + ] }, { -op => [ + '=', { -ident => [ 'employees', 'id' ] }, + { -ident => [ 'accounts', 'sales_person' ] }, + ] }, + ] }, + } } + + # query + UPDATE employees SET sales_count = sales_count + 1 FROM accounts + WHERE ( + accounts.name = 'Acme Corporation' + AND employees.id = accounts.sales_person + ) + [] + +=head2 delete using clause + +Some databases allow an additional USING clause to reference other tables +for the data to update; this clause is expanded as a normal from list, check +your database for what is and isn't allowed in practice. + + # expr + { -delete => { + from => 'x', + using => 'y', + where => { 'x.id' => { -ident => 'y.x_id' } }, + } } + + # aqt + { -delete => { + target => { -op => [ ',', { -ident => [ 'x' ] } ] }, + using => { -ident => [ 'y' ] }, + where => { -op => [ + '=', { -ident => [ 'x', 'id' ] }, + { -ident => [ 'y', 'x_id' ] }, + ] }, + } } + + # query + DELETE FROM x USING y WHERE x.id = y.x_id + [] + +=head2 insert rowvalues and select clauses + +rowvalues and select are shorthand for + + { from => { -select ... } } + +and + + { from => { -values ... } } + +respectively: + + # expr + { -insert => + { into => 'numbers', rowvalues => [ [ 1, 2 ], [ 3, 4 ], [ 5, 6 ] ] } + } + + # aqt + { -insert => { + from => { -values => [ + { -row => + [ { -bind => [ undef, 1 ] }, { -bind => [ undef, 2 ] } ] + }, + { -row => + [ { -bind => [ undef, 3 ] }, { -bind => [ undef, 4 ] } ] + }, + { -row => + [ { -bind => [ undef, 5 ] }, { -bind => [ undef, 6 ] } ] + }, + ] }, + target => { -ident => [ 'numbers' ] }, + } } + + # query + INSERT INTO numbers VALUES (?, ?), (?, ?), (?, ?) + [ 1, 2, 3, 4, 5, 6 ] + + # expr + { -insert => + { into => 'numbers', select => { _ => '*', from => 'old_numbers' } } + } + + # aqt + { -insert => { + from => { -select => { + from => { -ident => [ 'old_numbers' ] }, + select => { -op => [ ',', { -ident => [ '*' ] } ] }, + } }, + target => { -ident => [ 'numbers' ] }, + } } + + # query + INSERT INTO numbers SELECT * FROM old_numbers + [] + +=head2 with and with_recursive clauses + +These clauses are available on select/insert/update/delete queries; check +your database for applicability (e.g. mysql supports all four but mariadb +only select). + +The value should be an arrayref of name/query pairs: + + # expr + { -select => { + from => 'foo', + select => '*', + with => [ 'foo', { -select => { select => \1 } } ], + } } + + # aqt + { -select => { + from => { -ident => [ 'foo' ] }, + select => { -op => [ ',', { -ident => [ '*' ] } ] }, + with => { queries => [ [ + { -ident => [ 'foo' ] }, { -select => + { select => { -op => [ ',', { -literal => [ 1 ] } ] } } + }, + ] ] }, + } } + + # query + WITH foo AS (SELECT 1) SELECT * FROM foo + [] + +A more complete example (designed for mariadb, (ab)using the fact that +mysqloids materialise subselects in FROM into an unindexed temp table to +circumvent the restriction that you can't select from the table you're +currently updating: + + # expr + { -update => { + _ => [ + 'tree_table', -join => { + as => 'tree', + on => { 'tree.id' => 'tree_with_path.id' }, + to => { -select => { + from => 'tree_with_path', + select => '*', + with_recursive => [ + [ 'tree_with_path', 'id', 'parent_id', 'path' ], + { -select => { + _ => [ + 'id', 'parent_id', { -as => [ + { -cast => { -as => [ 'id', 'char', 255 ] } }, + 'path', + ] } ], + from => 'tree_table', + union_all => { -select => { + _ => [ + 't.id', 't.parent_id', { -as => [ + { -concat => [ 'r.path', \"'/'", 't.id' ] }, + 'path', + ] }, + ], + from => [ + 'tree_table', -as => 't', -join => { + as => 'r', + on => { 't.parent_id' => 'r.id' }, + to => 'tree_with_path', + }, + ], + } }, + where => { parent_id => undef }, + } }, + ], + } }, + }, + ], + set => { path => { -ident => [ 'tree', 'path' ] } }, + } } + + # query + UPDATE + tree_table JOIN + ( + WITH RECURSIVE + tree_with_path(id, parent_id, path) AS ( + ( + SELECT id, parent_id, CAST(id AS char(255)) AS path + FROM tree_table WHERE parent_id IS NULL + ) UNION ALL ( + SELECT t.id, t.parent_id, CONCAT(r.path, '/', t.id) AS path + FROM + tree_table AS t JOIN tree_with_path AS r ON + t.parent_id = r.id + ) + ) + SELECT * FROM tree_with_path + ) AS tree + ON tree.id = tree_with_path.id + SET path = tree.path + [] + +=cut