How to Use __in Lookup in Django Querysets

In Django, use the __in lookup to filter querysets by checking if a field's value is in a list or iterable. For example, Model.objects.filter(field__in=[value1, value2]) returns objects where field matches any value in the list.

Syntax

The __in lookup is used with Django queryset filters to check if a field's value is inside a given list or iterable.

• Model.objects.filter(field__in=iterable): Returns objects where field matches any item in iterable.
• field: The model field you want to filter on.
• iterable: A list, tuple, or any iterable containing values to match.

python

Model.objects.filter(field__in=[value1, value2, value3])

Example

This example shows how to filter Book objects whose id is in a list of IDs.

python

from django.db import models

class Book(models.Model):
    title = models.CharField(max_length=100)

# Assume we have books with IDs 1, 2, 3, 4, 5

# Filter books with IDs 2, 4, and 5
books = Book.objects.filter(id__in=[2, 4, 5])

for book in books:
    print(book.title)

Output

The output will list the titles of books with IDs 2, 4, and 5.

Common Pitfalls

Common mistakes when using __in include:

• Passing a non-iterable value (like a single integer) instead of a list or tuple.
• Using an empty list, which returns no results.
• Confusing __in with __exact which matches a single value.

Example of wrong and right usage:

python

# Wrong: passing a single value instead of a list
books_wrong = Book.objects.filter(id__in=5)  # This will raise a TypeError

# Right: passing a list
books_right = Book.objects.filter(id__in=[5])

Quick Reference

Usage	Description
field__in=[val1, val2]	Filters objects where field matches any value in the list
field__in=iterable	Accepts any iterable like list, tuple, or queryset
field__in=[]	Returns empty queryset (no matches)
field__in=single_value	Incorrect: must be iterable, not single value

Key Takeaways

Use __in lookup to filter queryset fields matching any value in a list or iterable.

Always pass an iterable (list, tuple, queryset) to __in, never a single value.

An empty list with __in returns no results.

Use __in for multiple value matching instead of multiple OR filters.

Check your iterable type to avoid errors with __in lookup.