From: Matt S Trout Date: Tue, 1 Oct 2019 20:15:47 +0000 (+0000) Subject: insert select/rowvalues clauses, with and with_recursive X-Git-Tag: v1.90_01~22 X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=e376aa8053a377ca85e9a16205132b30436b2ce5;p=dbsrgits%2FSQL-Abstract.git insert select/rowvalues clauses, with and with_recursive --- diff --git a/lib/SQL/Abstract/ExtraClauses.pm b/lib/SQL/Abstract/ExtraClauses.pm index 7d576bf..e1029bc 100644 --- a/lib/SQL/Abstract/ExtraClauses.pm +++ b/lib/SQL/Abstract/ExtraClauses.pm @@ -773,9 +773,6 @@ your database for what is and isn't allowed in practice. accounts.name = 'Acme Corporation' AND employees.id = accounts.sales_person ) - - [] - [] =head2 delete using clause @@ -805,4 +802,158 @@ your database for what is and isn't allowed in practice. 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 diff --git a/maint/podregen b/maint/podregen index 9869868..f07609f 100755 --- a/maint/podregen +++ b/maint/podregen @@ -52,7 +52,7 @@ while ($slurp =~ m/\G$expr_re/gc) { print $qpre.$qindent.$qtype; my ($sql, @bind) = $sqla->render_statement($expr); my $fsql = (ref($sql) ? $sqlaf->format(@$sql) : $sql); - $fsql =~ s/^/$indent/mg; + s/^/$indent/mg, s/\n+\Z// for $fsql; print $fsql."\n"; print reformat(\@bind, $qindent); print "\n";