Adding missing GroupConcat features issue #1101

src/django_mysql/models/aggregates.py

@@ -1,6 +1,8 @@
 from __future__ import annotations
 
 from typing import Any
+from typing import List  # noqa: F401
+from typing import Union  # noqa: F401
 
 from django.db.backends.base.base import BaseDatabaseWrapper
 from django.db.models import Aggregate
@@ -33,6 +35,7 @@ def __init__(
         distinct: bool = False,
         separator: str | None = None,
         ordering: str | None = None,
+        column_order: list[str] | str | None = None,
         **extra: Any,
     ) -> None:
         if "output_field" not in extra:
@@ -46,7 +49,13 @@ def __init__(
 
         if ordering not in ("asc", "desc", None):
             raise ValueError("'ordering' must be one of 'asc', 'desc', or None")
+        if ordering is not None:
+            if column_order is not None and isinstance(column_order, list):
+                raise ValueError(
+                    "When having a list in column_order, you can specify the ordering of each column inside the list. Example: ['column_a DESC',...]"
+                )
         self.ordering = ordering
+        self.column_order = column_order
 
     def as_sql(
         self,
@@ -69,12 +78,21 @@ def as_sql(
 
         sql.append(expr_sql)
 
-        if self.ordering is not None:
+        if self.ordering is not None or self.column_order is not None:
             sql.append(" ORDER BY ")
-            sql.append(expr_sql)
-            params.extend(params[:])
-            sql.append(" ")
-            sql.append(self.ordering.upper())
+
+            if self.column_order is not None:
+                if isinstance(self.column_order, str):
+                    sql.append(self.column_order)
+                if isinstance(self.column_order, list):
+                    sql.append(", ".join(self.column_order))
+            else:
+                sql.append(expr_sql)
+                params.extend(params[:])
+
+            if self.ordering is not None and not isinstance(self.column_order, list):
+                sql.append(" ")
+                sql.append(self.ordering.upper())
 
         if self.separator is not None:
             sql.append(f" SEPARATOR '{self.separator}'")  # noqa: B028

tests/testapp/test_aggregates.py

@@ -74,16 +74,26 @@ class GroupConcatTests(TestCase):
     shakes: Author
     jk: Author
     grisham: Author
+    agatha: Author
     str_tutee_ids: list[str]
 
     @classmethod
     def setUpTestData(cls):
         super().setUpTestData()
-        cls.shakes = Author.objects.create(name="William Shakespeare")
-        cls.jk = Author.objects.create(name="JK Rowling", tutor=cls.shakes)
-        cls.grisham = Author.objects.create(name="Grisham", tutor=cls.shakes)
+        cls.shakes = Author.objects.create(
+            name="William Shakespeare", bio="British author."
+        )
+        cls.jk = Author.objects.create(
+            name="JK Rowling", tutor=cls.shakes, bio="British author."
+        )
+        cls.grisham = Author.objects.create(
+            name="Grisham", tutor=cls.shakes, bio="American author."
+        )
+        cls.agatha = Author.objects.create(
+            name="Agatha Christie", tutor=cls.shakes, bio="British author."
+        )
 
-        cls.str_tutee_ids = [str(cls.jk.id), str(cls.grisham.id)]
+        cls.str_tutee_ids = [str(cls.jk.id), str(cls.grisham.id), str(cls.agatha.id)]
 
     def test_basic_aggregate_ids(self):
         out = self.shakes.tutees.aggregate(tids=GroupConcat("id"))
@@ -124,7 +134,9 @@ def test_separator_big(self):
     def test_expression(self):
         concat = GroupConcat(F("id") + 1)
         out = self.shakes.tutees.aggregate(tids=concat)
-        concatted_ids = ",".join([str(self.jk.id + 1), str(self.grisham.id + 1)])
+        concatted_ids = ",".join(
+            [str(self.jk.id + 1), str(self.grisham.id + 1), str(self.agatha.id + 1)]
+        )
         assert out == {"tids": concatted_ids}
 
     def test_application_order(self):
@@ -158,3 +170,21 @@ def test_separator_ordering(self):
         out = self.shakes.tutees.aggregate(tids=concat)
         concatted_ids = ":".join(self.str_tutee_ids)
         assert out == {"tids": concatted_ids}
+
+    def test_multiple_column_ordering(self):
+        concat = GroupConcat("id", column_order=["bio", "name desc"])
+        out = self.shakes.tutees.aggregate(tids=concat)
+        concatted_ids = ",".join(
+            [str(self.grisham.id), str(self.jk.id), str(self.agatha.id)]
+        )
+
+        assert out == {"tids": concatted_ids}
+
+    def test_multiple_column_ordering_2(self):
+        concat = GroupConcat("id", column_order="name")
+        out = self.shakes.tutees.aggregate(tids=concat)
+        concatted_ids = ",".join(
+            [str(self.agatha.id), str(self.grisham.id), str(self.jk.id)]
+        )
+
+        assert out == {"tids": concatted_ids}