Merge "Implement support for functions as FROM with columns clause support"

1 files changed, 123 insertions, 52 deletions

diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py
index 3d6643503..c6eae739d 100644
--- a/lib/sqlalchemy/sql/elements.py
+++ b/lib/sqlalchemy/sql/elements.py
@@ -3856,6 +3856,8 @@ class Over(ColumnElement):
 
         .. seealso::
 
+            :ref:`tutorial_window_functions` - in the :ref:`unified_tutorial`
+
             :data:`.expression.func`
 
             :func:`_expression.within_group`
@@ -4007,6 +4009,9 @@ class WithinGroup(ColumnElement):
 
         .. seealso::
 
+            :ref:`tutorial_functions_within_group` - in the
+            :ref:`unified_tutorial`
+
             :data:`.expression.func`
 
             :func:`_expression.over`
@@ -4104,8 +4109,10 @@ class FunctionFilter(ColumnElement):
 
         .. seealso::
 
-            :meth:`.FunctionElement.filter`
+            :ref:`tutorial_functions_within_group` - in the
+            :ref:`unified_tutorial`
 
+            :meth:`.FunctionElement.filter`
 
         """
         self.func = func
@@ -4317,11 +4324,82 @@ class Label(roles.LabeledColumnExprRole, ColumnElement):
         return self.key, e
 
 
+class NamedColumn(ColumnElement):
+    is_literal = False
+    table = None
+
+    def _compare_name_for_result(self, other):
+        return (hasattr(other, "name") and self.name == other.name) or (
+            hasattr(other, "_label") and self._label == other._label
+        )
+
+    @util.memoized_property
+    def description(self):
+        if util.py3k:
+            return self.name
+        else:
+            return self.name.encode("ascii", "backslashreplace")
+
+    @HasMemoized.memoized_attribute
+    def _key_label(self):
+        if self.key != self.name:
+            return self._gen_label(self.key)
+        else:
+            return self._label
+
+    @HasMemoized.memoized_attribute
+    def _label(self):
+        return self._gen_label(self.name)
+
+    @HasMemoized.memoized_attribute
+    def _render_label_in_columns_clause(self):
+        return True
+
+    def _gen_label(self, name, dedupe_on_key=True):
+        return name
+
+    def _bind_param(self, operator, obj, type_=None, expanding=False):
+        return BindParameter(
+            self.key,
+            obj,
+            _compared_to_operator=operator,
+            _compared_to_type=self.type,
+            type_=type_,
+            unique=True,
+            expanding=expanding,
+        )
+
+    def _make_proxy(
+        self,
+        selectable,
+        name=None,
+        name_is_truncatable=False,
+        disallow_is_literal=False,
+        **kw
+    ):
+        c = ColumnClause(
+            coercions.expect(roles.TruncatedLabelRole, name or self.name)
+            if name_is_truncatable
+            else (name or self.name),
+            type_=self.type,
+            _selectable=selectable,
+            is_literal=False,
+        )
+        c._propagate_attrs = selectable._propagate_attrs
+        if name is None:
+            c.key = self.key
+        c._proxies = [self]
+        if selectable._is_clone_of is not None:
+            c._is_clone_of = selectable._is_clone_of.columns.get(c.key)
+        return c.key, c
+
+
 class ColumnClause(
     roles.DDLReferredColumnRole,
     roles.LabeledColumnExprRole,
+    roles.StrAsPlainColumnRole,
     Immutable,
-    ColumnElement,
+    NamedColumn,
 ):
     """Represents a column expression from any textual string.
 
@@ -4360,6 +4438,9 @@ class ColumnClause(
 
     """
 
+    table = None
+    is_literal = False
+
     __visit_name__ = "column"
 
     _traverse_internals = [
@@ -4470,27 +4551,6 @@ class ColumnClause(
         self.type = type_api.to_instance(type_)
         self.is_literal = is_literal
 
-    def _compare_name_for_result(self, other):
-        if (
-            self.is_literal
-            or self.table is None
-            or self.table._is_textual
-            or not hasattr(other, "proxy_set")
-            or (
-                isinstance(other, ColumnClause)
-                and (
-                    other.is_literal
-                    or other.table is None
-                    or other.table._is_textual
-                )
-            )
-        ):
-            return (hasattr(other, "name") and self.name == other.name) or (
-                hasattr(other, "_label") and self._label == other._label
-            )
-        else:
-            return other.proxy_set.intersection(self.proxy_set)
-
     def get_children(self, column_tables=False, **kw):
         # override base get_children() to not return the Table
         # or selectable that is parent to this column.  Traversals
@@ -4505,24 +4565,6 @@ class ColumnClause(
         else:
             return []
 
-    @util.memoized_property
-    def description(self):
-        if util.py3k:
-            return self.name
-        else:
-            return self.name.encode("ascii", "backslashreplace")
-
-    @HasMemoized.memoized_attribute
-    def _key_label(self):
-        if self.key != self.name:
-            return self._gen_label(self.key)
-        else:
-            return self._label
-
-    @HasMemoized.memoized_attribute
-    def _label(self):
-        return self._gen_label(self.name)
-
     @HasMemoized.memoized_attribute
     def _render_label_in_columns_clause(self):
         return self.table is not None
@@ -4531,6 +4573,27 @@ class ColumnClause(
     def _ddl_label(self):
         return self._gen_label(self.name, dedupe_on_key=False)
 
+    def _compare_name_for_result(self, other):
+        if (
+            self.is_literal
+            or self.table is None
+            or self.table._is_textual
+            or not hasattr(other, "proxy_set")
+            or (
+                isinstance(other, ColumnClause)
+                and (
+                    other.is_literal
+                    or other.table is None
+                    or other.table._is_textual
+                )
+            )
+        ):
+            return (hasattr(other, "name") and self.name == other.name) or (
+                hasattr(other, "_label") and self._label == other._label
+            )
+        else:
+            return other.proxy_set.intersection(self.proxy_set)
+
     def _gen_label(self, name, dedupe_on_key=True):
         t = self.table
         if self.is_literal:
@@ -4575,17 +4638,6 @@ class ColumnClause(
         else:
             return name
 
-    def _bind_param(self, operator, obj, type_=None, expanding=False):
-        return BindParameter(
-            self.key,
-            obj,
-            _compared_to_operator=operator,
-            _compared_to_type=self.type,
-            type_=type_,
-            unique=True,
-            expanding=expanding,
-        )
-
     def _make_proxy(
         self,
         selectable,
@@ -4627,6 +4679,25 @@ class ColumnClause(
         return c.key, c
 
 
+class TableValuedColumn(NamedColumn):
+    __visit_name__ = "table_valued_column"
+
+    _traverse_internals = [
+        ("name", InternalTraversal.dp_anon_name),
+        ("type", InternalTraversal.dp_type),
+        ("scalar_alias", InternalTraversal.dp_clauseelement),
+    ]
+
+    def __init__(self, scalar_alias, type_):
+        self.scalar_alias = scalar_alias
+        self.key = self.name = scalar_alias.name
+        self.type = type_
+
+    @property
+    def _from_objects(self):
+        return [self.scalar_alias]
+
+
 class CollationClause(ColumnElement):
     __visit_name__ = "collation"