Reference QuerySet API reference

classVariance(expression,output_field=None,sample=False,filter=None,default=None,**extra)[source] : Returns the variance of the data in the provided expression.

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Reference QuerySet API reference

classStringAgg(expression,delimiter,output_field=None,distinct=False,filter=None,order_by=None,default=None,**extra)[source] : Returns the input values concatenated into a string, separated by the delimiter string, or default if there are no values.

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Reference QuerySet API reference

classPrefetch(lookup,queryset=None,to_attr=None)[source] The Prefetch() object can be used to control the operation of prefetch_related(). The lookup argument describes the relations to follow and works the same as the string based lookups passed to prefetch_related().

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Reference QuerySet API reference

This is useful in code that receives a list of model instances as opposed to a QuerySet; for example, when fetching models from a cache or instantiating them manually.

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Reference QuerySet API reference

… find restaurants that have vegetarian pizzas with 'mozzarella' in the name: If there are a large number of pizzas, this queryset performs better than: because the filtering in the WHERE clause of the first queryset will only operate on vegetarian …

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Reference QuerySet API reference QuerySet APIMethods that return new QuerySets

filter(*args,**kwargs) Returns a new QuerySet containing objects that match the given lookup parameters. The lookup parameters (**kwargs) should be in the format described in Field lookups below. Multiple parameters are joined via AND in the underlying SQL statement.

Reference QuerySet API reference QuerySet APIMethods that return new QuerySets

exclude(*args,**kwargs) Returns a new QuerySet containing objects that do not match the given lookup parameters. The lookup parameters (**kwargs) should be in the format described in Field lookups below.

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Reference QuerySet API reference QuerySet APIMethods that return new QuerySets

annotate(*args,**kwargs) Annotates each object in the QuerySet with the provided list of query expressions or Q objects.

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Reference QuerySet API reference QuerySet APIMethods that return new QuerySets

alias(*args,**kwargs) Same as annotate(), but instead of annotating objects in the QuerySet, saves the expression for later reuse with other QuerySet methods.

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Reference QuerySet API reference QuerySet APIMethods that return new QuerySets

order_by(*fields) By default, results returned by a QuerySet are ordered by the ordering tuple given by the ordering option in the model’s Meta. You can override this on a per-QuerySet basis by using the order_by method.

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Reference QuerySet API reference QuerySet APIMethods that return new QuerySets

reverse() Use the reverse() method to reverse the order in which a queryset’s elements are returned. Calling reverse() a second time restores the ordering back to the normal direction.

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Reference QuerySet API reference QuerySet APIMethods that return new QuerySets

distinct(*fields) Returns a new QuerySet that uses SELECT DISTINCT in its SQL query. This eliminates duplicate rows from the query results. By default, a QuerySet will not eliminate duplicate rows.

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Reference QuerySet API reference QuerySet APIMethods that return new QuerySets

values(*fields,**expressions) Returns a QuerySet that returns dictionaries, rather than model instances, when used as an iterable. Each of those dictionaries represents an object, with the keys corresponding to the attribute names of model objects.

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Reference QuerySet API reference QuerySet APIMethods that return new QuerySets

dates(field,kind,order='ASC') Returns a QuerySet that evaluates to a list of datetime.date objects representing all available dates of a particular kind within the contents of the QuerySet. field should be the name of a DateField of your model.

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Reference QuerySet API reference QuerySet APIMethods that return new QuerySets

datetimes(field_name,kind,order='ASC',tzinfo=None) Returns a QuerySet that evaluates to a list of datetime.datetime objects representing all available dates of a particular kind within the contents of the QuerySet. field_name should be the name of a DateTimeField of your model.

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Reference QuerySet API reference QuerySet APIMethods that return new QuerySets

none() Calling none() will create a queryset that never returns any objects and no query will be executed when accessing the results. A qs.none() queryset is an instance of EmptyQuerySet. Examples:

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Reference QuerySet API reference QuerySet APIMethods that return new QuerySets

all() Returns a copy of the current QuerySet (or QuerySet subclass). This can be useful in situations where you might want to pass in either a model manager or a QuerySet and do further filtering on the result.

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Reference QuerySet API reference QuerySet APIMethods that return new QuerySets

union(*other_qs,all=False) Uses SQL’s UNION operator to combine the results of two or more QuerySets. For example: The UNION operator selects only distinct values by default. To allow duplicate values, use the all=True argument.

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Reference QuerySet API reference QuerySet APIMethods that return new QuerySets

intersection(*other_qs) Uses SQL’s INTERSECT operator to return the shared elements of two or more QuerySets. For example: See union() for some restrictions.

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Reference QuerySet API reference QuerySet APIMethods that return new QuerySets

difference(*other_qs) Uses SQL’s EXCEPT operator to keep only elements present in the QuerySet but not in some other QuerySets. For example: See union() for some restrictions.

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