Implement last for querysets and models

CONTRIBUTORS.rst

@@ -60,6 +60,7 @@ Contributors
 * Abdeldjalil Hezouat ``@Abdeldjalil-H``
 * Andrea Magistà ``@vlakius``
 * Daniel Szucs ``@Quasar6X``
+* Rui Catarino ``@ruitcatarino``
 
 Special Thanks
 ==============

tests/test_model_methods.py

@@ -210,6 +210,10 @@ async def test_first(self):
         mdl = await self.cls.first()
         self.assertEqual(self.mdl.id, mdl.id)
 
+    async def test_last(self):
+        mdl = await self.cls.last()
+        self.assertEqual(self.mdl.id, mdl.id)
+
     async def test_latest(self):
         mdl = await self.cls.latest("name")
         self.assertEqual(self.mdl.id, mdl.id)

tests/test_queryset.py

@@ -272,6 +272,35 @@ async def test_first(self):
             None,
         )
 
+    async def test_last(self):
+        self.assertEqual(
+            (await IntFields.all().order_by("intnum").filter(intnum__gte=40).last()).intnum, 97
+        )
+        self.assertEqual(
+            (await IntFields.all().order_by("intnum").filter(intnum__gte=40).last().values())[
+                "intnum"
+            ],
+            97,
+        )
+        self.assertEqual(
+            (await IntFields.all().order_by("intnum").filter(intnum__gte=40).last().values_list())[
+                1
+            ],
+            97,
+        )
+
+        self.assertEqual(
+            await IntFields.all().order_by("intnum").filter(intnum__gte=400).last(), None
+        )
+        self.assertEqual(
+            await IntFields.all().order_by("intnum").filter(intnum__gte=400).last().values(), None
+        )
+        self.assertEqual(
+            await IntFields.all().order_by("intnum").filter(intnum__gte=400).last().values_list(),
+            None,
+        )
+        self.assertEqual((await IntFields.all().filter(intnum__gte=40).last()).intnum, 97)
+
     async def test_latest(self):
         self.assertEqual((await IntFields.all().latest("intnum")).intnum, 97)
         self.assertEqual(

tortoise/models.py

@@ -1247,6 +1247,13 @@ def first(cls, using_db: Optional[BaseDBAsyncClient] = None) -> QuerySetSingle[O
         """
         return cls._db_queryset(using_db).first()
 
+    @classmethod
+    def last(cls, using_db: Optional[BaseDBAsyncClient] = None) -> QuerySetSingle[Optional[Self]]:
+        """
+        Generates a QuerySet that returns the last record.
+        """
+        return cls._db_queryset(using_db).last()
+
     @classmethod
     def filter(cls, *args: Q, **kwargs: Any) -> QuerySet[Self]:
         """

tortoise/queryset.py

@@ -789,6 +789,29 @@ def first(self) -> QuerySetSingle[Optional[MODEL]]:
         queryset._single = True
         return queryset  # type: ignore
 
+    def last(self) -> QuerySetSingle[Optional[MODEL]]:
+        """
+        Limit queryset to one object and return the last object instead of list.
+        """
+        queryset = self._clone()
+
+        if queryset._orderings:
+            new_ordering = [
+                (field, Order.desc if order_type == Order.asc else Order.asc)
+                for field, order_type in queryset._orderings
+            ]
+        elif pk := self.model._meta.pk:
+            new_ordering = [(pk.model_field_name, Order.desc)]
+        else:
+            raise FieldError(
+                f"QuerySet has no ordering and model {self.model.__name__} has no pk defined"
+            )
+
+        queryset._orderings = new_ordering
+        queryset._limit = 1
+        queryset._single = True
+        return queryset  # type: ignore
+
     def get(self, *args: Q, **kwargs: Any) -> QuerySetSingle[MODEL]:
         """
         Fetch exactly one object matching the parameters.