diff --git a/AUTHORS b/AUTHORS index 420d1099058..0a50781b2c8 100644 --- a/AUTHORS +++ b/AUTHORS @@ -49,7 +49,7 @@ answer newbie questions, and generally made Django that much better: Andrew Godwin Andrew Pinkham Andrews Medina - Andriy Sokolovskiy + Andriy Sokolovskiy Andy Dustman Andy Gayton andy@jadedplanet.net diff --git a/django/contrib/postgres/aggregates/__init__.py b/django/contrib/postgres/aggregates/__init__.py new file mode 100644 index 00000000000..4bfbd526f7c --- /dev/null +++ b/django/contrib/postgres/aggregates/__init__.py @@ -0,0 +1,2 @@ +from .general import * # NOQA +from .statistics import * # NOQA diff --git a/django/contrib/postgres/aggregates/general.py b/django/contrib/postgres/aggregates/general.py new file mode 100644 index 00000000000..1dda69c4498 --- /dev/null +++ b/django/contrib/postgres/aggregates/general.py @@ -0,0 +1,43 @@ +from django.db.models.aggregates import Aggregate + +__all__ = [ + 'ArrayAgg', 'BitAnd', 'BitOr', 'BoolAnd', 'BoolOr', 'StringAgg', +] + + +class ArrayAgg(Aggregate): + function = 'ARRAY_AGG' + + def convert_value(self, value, expression, connection, context): + if not value: + return [] + return value + + +class BitAnd(Aggregate): + function = 'BIT_AND' + + +class BitOr(Aggregate): + function = 'BIT_OR' + + +class BoolAnd(Aggregate): + function = 'BOOL_AND' + + +class BoolOr(Aggregate): + function = 'BOOL_OR' + + +class StringAgg(Aggregate): + function = 'STRING_AGG' + template = "%(function)s(%(expressions)s, '%(delimiter)s')" + + def __init__(self, expression, delimiter, **extra): + super(StringAgg, self).__init__(expression, delimiter=delimiter, **extra) + + def convert_value(self, value, expression, connection, context): + if not value: + return '' + return value diff --git a/django/contrib/postgres/aggregates/statistics.py b/django/contrib/postgres/aggregates/statistics.py new file mode 100644 index 00000000000..89949580be0 --- /dev/null +++ b/django/contrib/postgres/aggregates/statistics.py @@ -0,0 +1,80 @@ +from django.db.models import FloatField, IntegerField +from django.db.models.aggregates import Aggregate + +__all__ = [ + 'CovarPop', 'Corr', 'RegrAvgX', 'RegrAvgY', 'RegrCount', 'RegrIntercept', + 'RegrR2', 'RegrSlope', 'RegrSXX', 'RegrSXY', 'RegrSYY', 'StatAggregate', +] + + +class StatAggregate(Aggregate): + def __init__(self, y, x, output_field=FloatField()): + if not x or not y: + raise ValueError('Both y and x must be provided.') + super(StatAggregate, self).__init__(y=y, x=x, output_field=output_field) + self.x = x + self.y = y + self.source_expressions = self._parse_expressions(self.y, self.x) + + def get_source_expressions(self): + return self.y, self.x + + def set_source_expressions(self, exprs): + self.y, self.x = exprs + + def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False): + return super(Aggregate, self).resolve_expression(query, allow_joins, reuse, summarize) + + +class Corr(StatAggregate): + function = 'CORR' + + +class CovarPop(StatAggregate): + def __init__(self, y, x, sample=False): + self.function = 'COVAR_SAMP' if sample else 'COVAR_POP' + super(CovarPop, self).__init__(y, x) + + +class RegrAvgX(StatAggregate): + function = 'REGR_AVGX' + + +class RegrAvgY(StatAggregate): + function = 'REGR_AVGY' + + +class RegrCount(StatAggregate): + function = 'REGR_COUNT' + + def __init__(self, y, x): + super(RegrCount, self).__init__(y=y, x=x, output_field=IntegerField()) + + def convert_value(self, value, expression, connection, context): + if value is None: + return 0 + return int(value) + + +class RegrIntercept(StatAggregate): + function = 'REGR_INTERCEPT' + + +class RegrR2(StatAggregate): + function = 'REGR_R2' + + +class RegrSlope(StatAggregate): + function = 'REGR_SLOPE' + + +class RegrSXX(StatAggregate): + function = 'REGR_SXX' + + +class RegrSXY(StatAggregate): + function = 'REGR_SXY' + + +class RegrSYY(StatAggregate): + function = 'REGR_SYY' diff --git a/docs/ref/contrib/postgres/aggregates.txt b/docs/ref/contrib/postgres/aggregates.txt new file mode 100644 index 00000000000..af4a0661b36 --- /dev/null +++ b/docs/ref/contrib/postgres/aggregates.txt @@ -0,0 +1,212 @@ +========================================= +PostgreSQL specific aggregation functions +========================================= + +.. module:: django.contrib.postgres.aggregates + :synopsis: PostgreSQL specific aggregation functions + +.. versionadded:: 1.9 + +These functions are described in more detail in the `PostgreSQL docs +`_. + +.. note:: + + All functions come without default aliases, so you must explicitly provide + one. For example:: + + >>> SomeModel.objects.aggregate(arr=ArrayAgg('somefield')) + {'arr': [0, 1, 2]} + +General-purpose aggregation functions +------------------------------------- + +ArrayAgg +~~~~~~~~ + +.. class:: ArrayAgg(expression, **extra) + + Returns a list of values, including nulls, concatenated into an array. + +BitAnd +~~~~~~ + +.. class:: BitAnd(expression, **extra) + + Returns an ``int`` of the bitwise ``AND`` of all non-null input values, or + ``None`` if all values are null. + +BitOr +~~~~~ + +.. class:: BitOr(expression, **extra) + + Returns an ``int`` of the bitwise ``OR`` of all non-null input values, or + ``None`` if all values are null. + +BoolAnd +~~~~~~~~ + +.. class:: BoolAnd(expression, **extra) + + Returns ``True``, if all input values are true, ``None`` if all values are + null or if there are no values, otherwise ``False`` . + +BoolOr +~~~~~~ + +.. class:: BoolOr(expression, **extra) + + Returns ``True`` if at least one input value is true, ``None`` if all + values are null or if there are no values, otherwise ``False``. + +StringAgg +~~~~~~~~~ + +.. class:: StringAgg(expression, delimiter) + + Returns the input values concatenated into a string, separated by + the ``delimiter`` string. + + .. attribute:: delimiter + + Required argument. Needs to be a string. + +Aggregate functions for statistics +---------------------------------- + +``y`` and ``x`` +~~~~~~~~~~~~~~~ + +The arguments ``y`` and ``x`` for all these functions can be the name of a +field or an expression returning a numeric data. Both are required. + +Corr +~~~~ + +.. class:: Corr(y, x) + + Returns the correlation coefficient as a ``float``, or ``None`` if there + aren't any matching rows. + +CovarPop +~~~~~~~~ + +.. class:: CovarPop(y, x, sample=False) + + Returns the population covariance as a ``float``, or ``None`` if there + aren't any matching rows. + + Has one optional argument: + + .. attribute:: sample + + By default ``CovarPop`` returns the general population covariance. + However, if ``sample=True``, the return value will be the sample + population covariance. + +RegrAvgX +~~~~~~~~ + +.. class:: RegrAvgX(y, x) + + Returns the average of the independent variable (``sum(x)/N``) as a + ``float``, or ``None`` if there aren't any matching rows. + +RegrAvgY +~~~~~~~~ + +.. class:: RegrAvgY(y, x) + + Returns the average of the independent variable (``sum(y)/N``) as a + ``float``, or ``None`` if there aren't any matching rows. + +RegrCount +~~~~~~~~~ + +.. class:: RegrCount(y, x) + + Returns an ``int`` of the number of input rows in which both expressions + are not null. + +RegrIntercept +~~~~~~~~~~~~~ + +.. class:: RegrIntercept(y, x) + + Returns the y-intercept of the least-squares-fit linear equation determined + by the ``(x, y)`` pairs as a ``float``, or ``None`` if there aren't any + matching rows. + +RegrR2 +~~~~~~ + +.. class:: RegrR2(y, x) + + Returns the square of the correlation coefficient as a ``float``, or + ``None`` if there aren't any matching rows. + +RegrSlope +~~~~~~~~~ + +.. class:: RegrSlope(y, x) + + Returns the slope of the least-squares-fit linear equation determined + by the ``(x, y)`` pairs as a ``float``, or ``None`` if there aren't any + matching rows. + +RegrSXX +~~~~~~~ + +.. class:: RegrSXX(y, x) + + Returns ``sum(x^2) - sum(x)^2/N`` ("sum of squares" of the independent + variable) as a ``float``, or ``None`` if there aren't any matching rows. + +RegrSXY +~~~~~~~ + +.. class:: RegrSXY(y, x) + + Returns ``sum(x*y) - sum(x) * sum(y)/N`` ("sum of products" of independent + times dependent variable) as a ``float``, or ``None`` if there aren't any + matching rows. + +RegrSYY +~~~~~~~ + +.. class:: RegrSYY(y, x) + + Returns ``sum(y^2) - sum(y)^2/N`` ("sum of squares" of the dependent + variable) as a ``float``, or ``None`` if there aren't any matching rows. + +Usage examples +-------------- + +We will use this example table:: + + | FIELD1 | FIELD2 | FIELD3 | + |--------|--------|--------| + | foo | 1 | 13 | + | bar | 2 | (null) | + | test | 3 | 13 | + + +Here's some examples of some of the general-purpose aggregation functions:: + + >>> TestModel.objects.aggregate(result=StringAgg('field1', delimiter=';')) + {'result': 'foo;bar;test'} + >>> TestModel.objects.aggregate(result=ArrayAgg('field2')) + {'result': [1, 2, 3]} + >>> TestModel.objects.aggregate(result=ArrayAgg('field1')) + {'result': ['foo', 'bar', 'test']} + +The next example shows the usage of statistical aggregate functions. The +underlying math will be not described (you can read about this, for example, at +`wikipedia `_):: + + >>> TestModel.objects.aggregate(count=RegrCount(y='field3', x='field2')) + {'count': 2} + >>> TestModel.objects.aggregate(avgx=RegrAvgX(y='field3', x='field2'), + ... avgy=RegrAvgY(y='field3', x='field2')) + {'avgx': 2, 'avgy': 13} diff --git a/docs/ref/contrib/postgres/index.txt b/docs/ref/contrib/postgres/index.txt index c97a61d123d..7ff66d07700 100644 --- a/docs/ref/contrib/postgres/index.txt +++ b/docs/ref/contrib/postgres/index.txt @@ -31,6 +31,7 @@ Psycopg2 2.5 or higher is required. .. toctree:: :maxdepth: 2 + aggregates fields forms lookups diff --git a/docs/releases/1.9.txt b/docs/releases/1.9.txt index aebdc7ba858..41ac4f27c96 100644 --- a/docs/releases/1.9.txt +++ b/docs/releases/1.9.txt @@ -69,6 +69,11 @@ Minor features * ... +:mod:`django.contrib.postgres` +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +* Added :doc:`/ref/contrib/postgres/aggregates`. + :mod:`django.contrib.redirects` ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/tests/postgres_tests/migrations/0002_create_test_models.py b/tests/postgres_tests/migrations/0002_create_test_models.py index c4f031f6d0e..7853f40a145 100644 --- a/tests/postgres_tests/migrations/0002_create_test_models.py +++ b/tests/postgres_tests/migrations/0002_create_test_models.py @@ -105,6 +105,24 @@ class Migration(migrations.Migration): options=None, bases=None, ), + migrations.CreateModel( + name='AggregateTestModel', + fields=[ + ('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)), + ('boolean_field', models.NullBooleanField()), + ('char_field', models.CharField(max_length=30, blank=True)), + ('integer_field', models.IntegerField(null=True)), + ] + ), + migrations.CreateModel( + name='StatTestModel', + fields=[ + ('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)), + ('int1', models.IntegerField()), + ('int2', models.IntegerField()), + ('related_field', models.ForeignKey('postgres_tests.AggregateTestModel', null=True)), + ] + ), ] pg_92_operations = [ diff --git a/tests/postgres_tests/models.py b/tests/postgres_tests/models.py index f698d56a586..b53eda4cca5 100644 --- a/tests/postgres_tests/models.py +++ b/tests/postgres_tests/models.py @@ -62,3 +62,21 @@ else: class ArrayFieldSubclass(ArrayField): def __init__(self, *args, **kwargs): super(ArrayFieldSubclass, self).__init__(models.IntegerField()) + + +class AggregateTestModel(models.Model): + """ + To test postgres-specific general aggregation functions + """ + char_field = models.CharField(max_length=30, blank=True) + integer_field = models.IntegerField(null=True) + boolean_field = models.NullBooleanField() + + +class StatTestModel(models.Model): + """ + To test postgres-specific aggregation functions for statistics + """ + int1 = models.IntegerField() + int2 = models.IntegerField() + related_field = models.ForeignKey(AggregateTestModel, null=True) diff --git a/tests/postgres_tests/test_aggregates.py b/tests/postgres_tests/test_aggregates.py new file mode 100644 index 00000000000..2857d917d51 --- /dev/null +++ b/tests/postgres_tests/test_aggregates.py @@ -0,0 +1,266 @@ +from django.contrib.postgres.aggregates import ( + ArrayAgg, BitAnd, BitOr, BoolAnd, BoolOr, Corr, CovarPop, RegrAvgX, + RegrAvgY, RegrCount, RegrIntercept, RegrR2, RegrSlope, RegrSXX, RegrSXY, + RegrSYY, StatAggregate, StringAgg, +) +from django.db.models.expressions import F, Value +from django.test import TestCase +from django.test.utils import Approximate + +from .models import AggregateTestModel, StatTestModel + + +class TestGeneralAggregate(TestCase): + @classmethod + def setUpTestData(cls): + AggregateTestModel.objects.create(boolean_field=True, char_field='Foo1', integer_field=0) + AggregateTestModel.objects.create(boolean_field=False, char_field='Foo2', integer_field=1) + AggregateTestModel.objects.create(boolean_field=False, char_field='Foo3', integer_field=2) + AggregateTestModel.objects.create(boolean_field=True, char_field='Foo4', integer_field=0) + + def test_array_agg_charfield(self): + values = AggregateTestModel.objects.aggregate(arrayagg=ArrayAgg('char_field')) + self.assertEqual(values, {'arrayagg': ['Foo1', 'Foo2', 'Foo3', 'Foo4']}) + + def test_array_agg_integerfield(self): + values = AggregateTestModel.objects.aggregate(arrayagg=ArrayAgg('integer_field')) + self.assertEqual(values, {'arrayagg': [0, 1, 2, 0]}) + + def test_array_agg_booleanfield(self): + values = AggregateTestModel.objects.aggregate(arrayagg=ArrayAgg('boolean_field')) + self.assertEqual(values, {'arrayagg': [True, False, False, True]}) + + def test_array_agg_empty_result(self): + AggregateTestModel.objects.all().delete() + values = AggregateTestModel.objects.aggregate(arrayagg=ArrayAgg('char_field')) + self.assertEqual(values, {'arrayagg': []}) + values = AggregateTestModel.objects.aggregate(arrayagg=ArrayAgg('integer_field')) + self.assertEqual(values, {'arrayagg': []}) + values = AggregateTestModel.objects.aggregate(arrayagg=ArrayAgg('boolean_field')) + self.assertEqual(values, {'arrayagg': []}) + + def test_bit_and_general(self): + values = AggregateTestModel.objects.filter( + integer_field__in=[0, 1]).aggregate(bitand=BitAnd('integer_field')) + self.assertEqual(values, {'bitand': 0}) + + def test_bit_and_on_only_true_values(self): + values = AggregateTestModel.objects.filter( + integer_field=1).aggregate(bitand=BitAnd('integer_field')) + self.assertEqual(values, {'bitand': 1}) + + def test_bit_and_on_only_false_values(self): + values = AggregateTestModel.objects.filter( + integer_field=0).aggregate(bitand=BitAnd('integer_field')) + self.assertEqual(values, {'bitand': 0}) + + def test_bit_and_empty_result(self): + AggregateTestModel.objects.all().delete() + values = AggregateTestModel.objects.aggregate(bitand=BitAnd('integer_field')) + self.assertEqual(values, {'bitand': None}) + + def test_bit_or_general(self): + values = AggregateTestModel.objects.filter( + integer_field__in=[0, 1]).aggregate(bitor=BitOr('integer_field')) + self.assertEqual(values, {'bitor': 1}) + + def test_bit_or_on_only_true_values(self): + values = AggregateTestModel.objects.filter( + integer_field=1).aggregate(bitor=BitOr('integer_field')) + self.assertEqual(values, {'bitor': 1}) + + def test_bit_or_on_only_false_values(self): + values = AggregateTestModel.objects.filter( + integer_field=0).aggregate(bitor=BitOr('integer_field')) + self.assertEqual(values, {'bitor': 0}) + + def test_bit_or_empty_result(self): + AggregateTestModel.objects.all().delete() + values = AggregateTestModel.objects.aggregate(bitor=BitOr('integer_field')) + self.assertEqual(values, {'bitor': None}) + + def test_bool_and_general(self): + values = AggregateTestModel.objects.aggregate(booland=BoolAnd('boolean_field')) + self.assertEqual(values, {'booland': False}) + + def test_bool_and_empty_result(self): + AggregateTestModel.objects.all().delete() + values = AggregateTestModel.objects.aggregate(booland=BoolAnd('boolean_field')) + self.assertEqual(values, {'booland': None}) + + def test_bool_or_general(self): + values = AggregateTestModel.objects.aggregate(boolor=BoolOr('boolean_field')) + self.assertEqual(values, {'boolor': True}) + + def test_bool_or_empty_result(self): + AggregateTestModel.objects.all().delete() + values = AggregateTestModel.objects.aggregate(boolor=BoolOr('boolean_field')) + self.assertEqual(values, {'boolor': None}) + + def test_string_agg_requires_delimiter(self): + with self.assertRaises(TypeError): + AggregateTestModel.objects.aggregate(stringagg=StringAgg('char_field')) + + def test_string_agg_charfield(self): + values = AggregateTestModel.objects.aggregate(stringagg=StringAgg('char_field', delimiter=';')) + self.assertEqual(values, {'stringagg': 'Foo1;Foo2;Foo3;Foo4'}) + + def test_string_agg_empty_result(self): + AggregateTestModel.objects.all().delete() + values = AggregateTestModel.objects.aggregate(stringagg=StringAgg('char_field', delimiter=';')) + self.assertEqual(values, {'stringagg': ''}) + + +class TestStatisticsAggregate(TestCase): + @classmethod + def setUpTestData(cls): + StatTestModel.objects.create( + int1=1, + int2=3, + related_field=AggregateTestModel.objects.create(integer_field=0), + ) + StatTestModel.objects.create( + int1=2, + int2=2, + related_field=AggregateTestModel.objects.create(integer_field=1), + ) + StatTestModel.objects.create( + int1=3, + int2=1, + related_field=AggregateTestModel.objects.create(integer_field=2), + ) + + # Tests for base class (StatAggregate) + + def test_missing_arguments_raises_exception(self): + with self.assertRaisesMessage(ValueError, 'Both y and x must be provided.'): + StatAggregate(x=None, y=None) + + def test_correct_source_expressions(self): + func = StatAggregate(x='test', y=13) + self.assertIsInstance(func.source_expressions[0], Value) + self.assertIsInstance(func.source_expressions[1], F) + + def test_alias_is_required(self): + class SomeFunc(StatAggregate): + function = 'TEST' + with self.assertRaisesMessage(TypeError, 'Complex aggregates require an alias'): + StatTestModel.objects.aggregate(SomeFunc(y='int2', x='int1')) + + # Test aggregates + + def test_corr_general(self): + values = StatTestModel.objects.aggregate(corr=Corr(y='int2', x='int1')) + self.assertEqual(values, {'corr': -1.0}) + + def test_corr_empty_result(self): + StatTestModel.objects.all().delete() + values = StatTestModel.objects.aggregate(corr=Corr(y='int2', x='int1')) + self.assertEqual(values, {'corr': None}) + + def test_covar_pop_general(self): + values = StatTestModel.objects.aggregate(covarpop=CovarPop(y='int2', x='int1')) + self.assertEqual(values, {'covarpop': Approximate(-0.66, places=1)}) + + def test_covar_pop_empty_result(self): + StatTestModel.objects.all().delete() + values = StatTestModel.objects.aggregate(covarpop=CovarPop(y='int2', x='int1')) + self.assertEqual(values, {'covarpop': None}) + + def test_covar_pop_sample(self): + values = StatTestModel.objects.aggregate(covarpop=CovarPop(y='int2', x='int1', sample=True)) + self.assertEqual(values, {'covarpop': -1.0}) + + def test_covar_pop_sample_empty_result(self): + StatTestModel.objects.all().delete() + values = StatTestModel.objects.aggregate(covarpop=CovarPop(y='int2', x='int1', sample=True)) + self.assertEqual(values, {'covarpop': None}) + + def test_regr_avgx_general(self): + values = StatTestModel.objects.aggregate(regravgx=RegrAvgX(y='int2', x='int1')) + self.assertEqual(values, {'regravgx': 2.0}) + + def test_regr_avgx_empty_result(self): + StatTestModel.objects.all().delete() + values = StatTestModel.objects.aggregate(regravgx=RegrAvgX(y='int2', x='int1')) + self.assertEqual(values, {'regravgx': None}) + + def test_regr_avgy_general(self): + values = StatTestModel.objects.aggregate(regravgy=RegrAvgY(y='int2', x='int1')) + self.assertEqual(values, {'regravgy': 2.0}) + + def test_regr_avgy_empty_result(self): + StatTestModel.objects.all().delete() + values = StatTestModel.objects.aggregate(regravgy=RegrAvgY(y='int2', x='int1')) + self.assertEqual(values, {'regravgy': None}) + + def test_regr_count_general(self): + values = StatTestModel.objects.aggregate(regrcount=RegrCount(y='int2', x='int1')) + self.assertEqual(values, {'regrcount': 3}) + + def test_regr_count_empty_result(self): + StatTestModel.objects.all().delete() + values = StatTestModel.objects.aggregate(regrcount=RegrCount(y='int2', x='int1')) + self.assertEqual(values, {'regrcount': 0}) + + def test_regr_intercept_general(self): + values = StatTestModel.objects.aggregate(regrintercept=RegrIntercept(y='int2', x='int1')) + self.assertEqual(values, {'regrintercept': 4}) + + def test_regr_intercept_empty_result(self): + StatTestModel.objects.all().delete() + values = StatTestModel.objects.aggregate(regrintercept=RegrIntercept(y='int2', x='int1')) + self.assertEqual(values, {'regrintercept': None}) + + def test_regr_r2_general(self): + values = StatTestModel.objects.aggregate(regrr2=RegrR2(y='int2', x='int1')) + self.assertEqual(values, {'regrr2': 1}) + + def test_regr_r2_empty_result(self): + StatTestModel.objects.all().delete() + values = StatTestModel.objects.aggregate(regrr2=RegrR2(y='int2', x='int1')) + self.assertEqual(values, {'regrr2': None}) + + def test_regr_slope_general(self): + values = StatTestModel.objects.aggregate(regrslope=RegrSlope(y='int2', x='int1')) + self.assertEqual(values, {'regrslope': -1}) + + def test_regr_slope_empty_result(self): + StatTestModel.objects.all().delete() + values = StatTestModel.objects.aggregate(regrslope=RegrSlope(y='int2', x='int1')) + self.assertEqual(values, {'regrslope': None}) + + def test_regr_sxx_general(self): + values = StatTestModel.objects.aggregate(regrsxx=RegrSXX(y='int2', x='int1')) + self.assertEqual(values, {'regrsxx': 2.0}) + + def test_regr_sxx_empty_result(self): + StatTestModel.objects.all().delete() + values = StatTestModel.objects.aggregate(regrsxx=RegrSXX(y='int2', x='int1')) + self.assertEqual(values, {'regrsxx': None}) + + def test_regr_sxy_general(self): + values = StatTestModel.objects.aggregate(regrsxy=RegrSXY(y='int2', x='int1')) + self.assertEqual(values, {'regrsxy': -2.0}) + + def test_regr_sxy_empty_result(self): + StatTestModel.objects.all().delete() + values = StatTestModel.objects.aggregate(regrsxy=RegrSXY(y='int2', x='int1')) + self.assertEqual(values, {'regrsxy': None}) + + def test_regr_syy_general(self): + values = StatTestModel.objects.aggregate(regrsyy=RegrSYY(y='int2', x='int1')) + self.assertEqual(values, {'regrsyy': 2.0}) + + def test_regr_syy_empty_result(self): + StatTestModel.objects.all().delete() + values = StatTestModel.objects.aggregate(regrsyy=RegrSYY(y='int2', x='int1')) + self.assertEqual(values, {'regrsyy': None}) + + def test_regr_avgx_with_related_obj_and_number_as_argument(self): + """ + This is more complex test to check if JOIN on field and + number as argument works as expected. + """ + values = StatTestModel.objects.aggregate(complex_regravgx=RegrAvgX(y=5, x='related_field__integer_field')) + self.assertEqual(values, {'complex_regravgx': 1.0})