A field lookup is essentially a way to specify how Django should filter query results based on a model field's value.

Basic Structure

A field lookup takes the form field__lookuptype=value. Here, field is the name of the model field, lookuptype is the type of comparison, and value is the value to compare against.

Common Field Lookups

• exact - the default lookup type; it performs case-sensitive comparisons.
  (SELECT * FROM Book WHERE genre = 'philosophy';)

Book.objects.filter(genre__exact="philosophy")

• iexact - case-insensitive match.
  (SELECT * FROM Author WHERE LOWER(pen_name) = LOWER('george orwell');)

Author.objects.filter(pen_name__iexact="george orwell")

• contains - case-sensitive containment test.
  (SELECT * FROM Book WHERE title LIKE '%House%';)

Book.objects.filter(title__contains="House")

• icontains - case-insensitive containment test.
  (SELECT * FROM Book WHERE LOWER(title) LIKE LOWER('%house%');)

Book.objects.filter(title__icontains="house")

• in - in a given iterable; often used for filtering by a list of values.
  (SELECT * FROM Author WHERE id IN (1, 4, 7);)

Author.objects.filter(pk__in=[1, 4, 7])

• gt, gte, lt, lte - greater than, greater than or equal to, less than, and less than or equal to.
  (SELECT * FROM Author WHERE id < 10;)

Author.objects.filter(pk__lt=10)

• startswith, istartswith - string starts with a value (case-sensitive and insensitive versions).
  (SELECT * FROM Author WHERE first_name LIKE 'J%';)

Author.objects.filter(first_name__startswith="J")

• endswith, iendswith - string ends with a value (case-sensitive and insensitive versions).
  (SELECT * FROM Author WHERE last_name LIKE '%e';)

Author.objects.filter(last_name__endswith="e")

• range - within a certain range (inclusive).
  (SELECT * FROM Book WHERE id BETWEEN 1 AND 5;)

Book.objects.filter(pk__range=(1, 5))

• date, year, month, day - specific date components.
  (SELECT * FROM Book WHERE EXTRACT(YEAR FROM pub_date) = 2023;)

Book.objects.filter(pub_date__year=2023)