PostgreSQL specific aggregation functions¶

ArrayAgg¶

class ArrayAgg(expression, distinct=False, filter=None, ordering=(), **extra)¶

Returns a list of values, including nulls, concatenated into an array.

distinct¶

An optional boolean argument that determines if array values will be distinct. Defaults to False.

ordering¶

An optional string of a field name (with an optional "-" prefix which indicates descending order) or an expression (or a tuple or list of strings and/or expressions) that specifies the ordering of the elements in the result list.

Examples:

'some_field'
'-some_field'
from django.db.models import F
F('some_field').desc()

BitAnd¶

class BitAnd(expression, filter=None, **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, filter=None, **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, filter=None, **extra)¶

Returns True, if all input values are true, None if all values are null or if there are no values, otherwise False .

Usage example:

class Comment(models.Model):
    body = models.TextField()
    published = models.BooleanField()
    rank = models.IntegerField()

>>> from django.db.models import Q
>>> from django.contrib.postgres.aggregates import BoolAnd
>>> Comment.objects.aggregate(booland=BoolAnd('published'))
{'booland': False}
>>> Comment.objects.aggregate(booland=BoolAnd(Q(rank__lt=100)))
{'booland': True}

BoolOr¶

class BoolOr(expression, filter=None, **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.

Usage example:

class Comment(models.Model):
    body = models.TextField()
    published = models.BooleanField()
    rank = models.IntegerField()

>>> from django.db.models import Q
>>> from django.contrib.postgres.aggregates import BoolOr
>>> Comment.objects.aggregate(boolor=BoolOr('published'))
{'boolor': True}
>>> Comment.objects.aggregate(boolor=BoolOr(Q(rank__gt=2)))
{'boolor': False}

JSONBAgg¶

class JSONBAgg(expressions, distinct=False, filter=None, ordering=(), **extra)¶

Returns the input values as a JSON array.

distinct¶

New in Django 3.2.

An optional boolean argument that determines if array values will be distinct. Defaults to False.

ordering¶

New in Django 3.2.

An optional string of a field name (with an optional "-" prefix which indicates descending order) or an expression (or a tuple or list of strings and/or expressions) that specifies the ordering of the elements in the result list.

Examples are the same as for ArrayAgg.ordering.

StringAgg¶

class StringAgg(expression, delimiter, distinct=False, filter=None, ordering=())¶

Returns the input values concatenated into a string, separated by the delimiter string.

delimiter¶

Required argument. Needs to be a string.

distinct¶

An optional boolean argument that determines if concatenated values will be distinct. Defaults to False.

ordering¶

An optional string of a field name (with an optional "-" prefix which indicates descending order) or an expression (or a tuple or list of strings and/or expressions) that specifies the ordering of the elements in the result string.

Examples are the same as for ArrayAgg.ordering.

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, filter=None)¶

Returns the correlation coefficient as a float, or None if there aren’t any matching rows.

CovarPop¶

class CovarPop(y, x, sample=False, filter=None)¶

Returns the population covariance as a float, or None if there aren’t any matching rows.

Has one optional argument:

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, filter=None)¶

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, filter=None)¶

Returns the average of the dependent variable (sum(y)/N) as a float, or None if there aren’t any matching rows.

RegrCount¶

class RegrCount(y, x, filter=None)¶

Returns an int of the number of input rows in which both expressions are not null.

RegrIntercept¶

class RegrIntercept(y, x, filter=None)¶

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, filter=None)¶

Returns the square of the correlation coefficient as a float, or None if there aren’t any matching rows.

RegrSlope¶

class RegrSlope(y, x, filter=None)¶

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, filter=None)¶

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, filter=None)¶

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, filter=None)¶

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.