From 0f91ba1adc037345474749faa64d36a4077b3fb8 Mon Sep 17 00:00:00 2001
From: Mariusz Felisiak <felisiak.mariusz@gmail.com>
Date: Wed, 21 Jun 2017 16:16:53 +0200
Subject: [PATCH] Fixed #28329 -- Fixed Cast() with
 Big/Small/Positive/PositiveSmallIntegerField on MySQL.

---
 django/db/models/functions/base.py |  4 ++++
 tests/db_functions/test_cast.py    | 14 +++++++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/django/db/models/functions/base.py b/django/db/models/functions/base.py
index 7fd396d609..c487bb4ab5 100644
--- a/django/db/models/functions/base.py
+++ b/django/db/models/functions/base.py
@@ -12,7 +12,11 @@ class Cast(Func):
     mysql_types = {
         fields.CharField: 'char',
         fields.IntegerField: 'signed integer',
+        fields.BigIntegerField: 'signed integer',
+        fields.SmallIntegerField: 'signed integer',
         fields.FloatField: 'signed',
+        fields.PositiveIntegerField: 'unsigned integer',
+        fields.PositiveSmallIntegerField: 'unsigned integer',
     }
 
     def __init__(self, expression, output_field):
diff --git a/tests/db_functions/test_cast.py b/tests/db_functions/test_cast.py
index 39d4f44f9c..70de20e5eb 100644
--- a/tests/db_functions/test_cast.py
+++ b/tests/db_functions/test_cast.py
@@ -9,7 +9,7 @@ from .models import Author
 class CastTests(TestCase):
     @classmethod
     def setUpTestData(self):
-        Author.objects.create(name='Bob', age=1)
+        Author.objects.create(name='Bob', age=1, alias='1')
 
     def test_cast_from_value(self):
         numbers = Author.objects.annotate(cast_integer=Cast(Value('0'), models.IntegerField()))
@@ -19,6 +19,18 @@ class CastTests(TestCase):
         numbers = Author.objects.annotate(cast_string=Cast('age', models.CharField(max_length=255)),)
         self.assertEqual(numbers.get().cast_string, '1')
 
+    def test_cast_to_integer(self):
+        for field_class in (
+            models.IntegerField,
+            models.BigIntegerField,
+            models.SmallIntegerField,
+            models.PositiveIntegerField,
+            models.PositiveSmallIntegerField,
+        ):
+            with self.subTest(field_class=field_class):
+                numbers = Author.objects.annotate(cast_int=Cast('alias', field_class()))
+                self.assertEqual(numbers.get().cast_int, 1)
+
     def test_cast_from_python(self):
         numbers = Author.objects.annotate(cast_float=Cast(0, models.FloatField()))
         self.assertEqual(numbers.get().cast_float, 0.0)