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=358cdf16f7e0ae0dd3e50669eb3d6c7ed3254ab3;hb=e376aa8053a377ca85e9a16205132b30436b2ce5;hpb=f1c52c0c610ec999b831c3a105d27c5b6f839a56

diff --git a/lib/SQL/Abstract/ExtraClauses.pm b/lib/SQL/Abstract/ExtraClauses.pm
index 358cdf1..e1029bc 100644
--- a/lib/SQL/Abstract/ExtraClauses.pm
+++ b/lib/SQL/Abstract/ExtraClauses.pm
@@ -5,7 +5,7 @@ use Moo;
 has sqla => (
   is => 'ro', init_arg => undef,
   handles => [ qw(
-    expand_expr expand_maybe_list_expr render_aqt join_query_parts
+    expand_expr render_aqt join_query_parts
   ) ],
 );
 
@@ -79,7 +79,7 @@ sub register_extensions {
     clause_expanders => [
       "select.from", '_expand_from_list',
       'select.group_by'
-        => sub { $_[0]->expand_maybe_list_expr($_[2], -ident) },
+        => sub { $_[0]->expand_expr({ -list => $_[2] }, -ident) },
       'select.having'
         => sub { $_[0]->expand_expr($_[2]) },
       'update.from' => '_expand_from_list',
@@ -104,7 +104,8 @@ sub register_extensions {
     clause_renderer => [
       'select.setop' => sub { $_[0]->render_aqt($_[2]) }
     ],
-    expander => [ map +($_ => '_expand_setop'), qw(union intersect except) ],
+    expander => [
+      map +($_ => '_expand_setop', "${_}_all" => '_expand_setop'), qw(union intersect except) ],
     renderer => [ map +($_ => '_render_setop'), qw(union intersect except) ],
   );
 
@@ -167,6 +168,7 @@ sub _expand_from_list {
     }
     push @list, $aqt;
   }
+  return $list[0] if @list == 1;
   return { -from_list => \@list };
 }
 
@@ -175,10 +177,12 @@ 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} = $self->expand_expr({ -as => [ $proto{to}, $as ] });
+    $proto{to} = $self->expand_expr(
+                   { -as => [ { -from_list => $proto{to} }, $as ] }
+                 );
   }
   if (defined($proto{using}) and ref(my $using = $proto{using}) ne 'HASH') {
     $proto{using} = [
@@ -186,8 +190,14 @@ sub _expand_join {
         ref($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 };
 }
 
@@ -202,7 +212,12 @@ sub _render_join {
   my @parts = (
     $args->{from},
     { -keyword => join '_', ($args->{type}||()), 'join' },
-    (map +($_->{-ident} || $_->{-as} ? $_ : ('(', $_, ')')), $args->{to}),
+    (map +($_->{-ident} || $_->{-as}
+      ? $_
+      : ('(', $self->render_aqt($_, 1), ')')),
+        map +(@{$_->{-from_list}||[]} == 1 ? $_->{-from_list}[0] : $_),
+          $args->{to}
+    ),
     ($args->{on} ? (
       { -keyword => 'on' },
       $args->{on},
@@ -219,11 +234,11 @@ sub _expand_op_as {
   my ($self, undef, $vv, $k) = @_;
   my @vv = (ref($vv) eq 'ARRAY' ? @$vv : $vv);
   my $ik = $self->expand_expr($k, -ident);
-  return +{ -as => [ $ik, $self->expand_expr($vv[0], -alias) ] }
+  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, { -alias => \@as } ] };
+  return { -as => [ $ik, $self->expand_expr({ -alias => \@as }) ] };
 }
 
 sub _render_as {
@@ -274,11 +289,10 @@ sub _expand_alias {
   if (ref($args) eq 'HASH' and my $alias = $args->{-alias}) {
     $args = $alias;
   }
-  +{ -alias => [
-      map $self->expand_expr($_, -ident),
-      ref($args) eq 'ARRAY' ? @{$args} : $args
-    ]
-  }
+  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 {
@@ -326,9 +340,16 @@ sub _render_with {
 
 sub _expand_setop {
   my ($self, $setop, $args) = @_;
+  my $is_all = $setop =~ s/_all$//;
   +{ "-${setop}" => {
-       %$args,
-       queries => [ map $self->expand_expr($_), @{$args->{queries}} ],
+       ($is_all ? (type => 'all') : ()),
+       (ref($args) eq 'ARRAY'
+          ? (queries => [ map $self->expand_expr($_), @$args ])
+          : (
+              %$args,
+              queries => [ map $self->expand_expr($_), @{$args->{queries}} ]
+            )
+       ),
   } };
 }
 
@@ -364,6 +385,11 @@ SQL::Abstract::ExtraClauses - new/experimental additions to L<SQL::Abstract>
   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
@@ -415,12 +441,7 @@ as a list of arguments for the alias node.
   { foo => { -as => 'bar' } }
 
   # aqt
-  { -as =>
-      [
-        { -ident => [ 'foo' ] },
-        { -alias => [ { -ident => [ 'bar' ] } ] },
-      ]
-  }
+  { -as => [ { -ident => [ 'foo' ] }, { -ident => [ 'bar' ] } ] }
 
   # query
   foo AS bar
@@ -457,4 +478,482 @@ as a list of arguments for the alias node.
   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