Browse Source

Refs #28333 -- Explicitly ordered outer qualify query on window filtering.

While most backends will propagate derived table ordering as long as
the outer query doesn't perform additional processing the SQL specs
doesn't explicitly state the ordering must be maintained.
Simon Charette 2 years ago
parent
commit
3ba7f2e906
1 changed files with 42 additions and 14 deletions
  1. 42 14
      django/db/models/sql/compiler.py

+ 42 - 14
django/db/models/sql/compiler.py

@@ -607,24 +607,41 @@ class SQLCompiler:
         select = {
             expr: alias for expr, _, alias in self.get_select(with_col_aliases=True)[0]
         }
+        select_aliases = set(select.values())
         qual_aliases = set()
         replacements = {}
-        expressions = list(self.qualify.leaves())
-        while expressions:
-            expr = expressions.pop()
-            if select_alias := (select.get(expr) or replacements.get(expr)):
-                replacements[expr] = select_alias
-            elif isinstance(expr, Lookup):
-                expressions.extend(expr.get_source_expressions())
-            else:
-                num_qual_alias = len(qual_aliases)
-                select_alias = f"qual{num_qual_alias}"
-                qual_aliases.add(select_alias)
-                inner_query.add_annotation(expr, select_alias)
-                replacements[expr] = select_alias
+
+        def collect_replacements(expressions):
+            while expressions:
+                expr = expressions.pop()
+                if expr in replacements:
+                    continue
+                elif select_alias := select.get(expr):
+                    replacements[expr] = select_alias
+                elif isinstance(expr, Lookup):
+                    expressions.extend(expr.get_source_expressions())
+                elif isinstance(expr, Ref):
+                    if expr.refs not in select_aliases:
+                        expressions.extend(expr.get_source_expressions())
+                else:
+                    num_qual_alias = len(qual_aliases)
+                    select_alias = f"qual{num_qual_alias}"
+                    qual_aliases.add(select_alias)
+                    inner_query.add_annotation(expr, select_alias)
+                    replacements[expr] = select_alias
+
+        collect_replacements(list(self.qualify.leaves()))
         self.qualify = self.qualify.replace_expressions(
             {expr: Ref(alias, expr) for expr, alias in replacements.items()}
         )
+        order_by = []
+        for order_by_expr, *_ in self.get_order_by():
+            collect_replacements(order_by_expr.get_source_expressions())
+            order_by.append(
+                order_by_expr.replace_expressions(
+                    {expr: Ref(alias, expr) for expr, alias in replacements.items()}
+                )
+            )
         inner_query_compiler = inner_query.get_compiler(
             self.using, elide_empty=self.elide_empty
         )
@@ -657,7 +674,18 @@ class SQLCompiler:
                 ")",
                 self.connection.ops.quote_name("qualify_mask"),
             ]
-        return result, list(inner_params) + qualify_params
+        params = list(inner_params) + qualify_params
+        # As the SQL spec is unclear on whether or not derived tables
+        # ordering must propagate it has to be explicitly repeated on the
+        # outer-most query to ensure it's preserved.
+        if order_by:
+            ordering_sqls = []
+            for ordering in order_by:
+                ordering_sql, ordering_params = self.compile(ordering)
+                ordering_sqls.append(ordering_sql)
+                params.extend(ordering_params)
+            result.extend(["ORDER BY", ", ".join(ordering_sqls)])
+        return result, params
 
     def as_sql(self, with_limits=True, with_col_aliases=False):
         """