Django values_list vs values

"values()" returns a QuerySet of dictionaries.

For example:

print(User.objects.all().values()) # Return all fields
# <QuerySet [{'id': 1, 'name': 'John'}, {'id': 2, 'name': 'Tom'}]>

print(User.objects.all().values("name")) # Return "name" field
# <QuerySet [{'name': 'John'}, {'name': 'Tom'}]>

"values_list()" returns a QuerySet of tuples.

For example:

print(User.objects.all().values_list()) # Return all fields
# <QuerySet [(1, 'John'), (2, 'Tom')]>

print(User.objects.all().values_list("name")) # Return "name" field
# <QuerySet [('John',), ('Tom',)]>

"values_list()" with "flat=True" returns a QuerySet of values. *No or One field with "flat=True" is allowed and one field must be the 1st argument with "flat=True" which must be the 2nd argument.

For example:

print(User.objects.all().values_list(flat=True)) # Return "id" field
# <QuerySet [1, 2]>

print(User.objects.all().values_list("name", flat=True)) # Return "name" field
# <QuerySet ['John', 'Tom']>

print(User.objects.all().values_list(flat=True, "name")) # Error

print(User.objects.all().values_list("id", "name", flat=True)) # Error

You can get the different values with:

set(Article.objects.values_list('comment_id', flat=True))

The values() method returns a QuerySet containing dictionaries:

<QuerySet [{'comment_id': 1}, {'comment_id': 2}]>

The values_list() method returns a QuerySet containing tuples:

<QuerySet [(1,), (2,)]>

If you are using values_list() with a single field, you can use flat=True to return a QuerySet of single values instead of 1-tuples:

<QuerySet [1, 2]>

values()

Returns a QuerySet that returns dictionaries, rather than model instances, when used as an iterable.

values_list()

Returns a QuerySet that returns list of tuples, rather than model instances, when used as an iterable.

distinct()

distinct are used to eliminate the duplicate elements.

Example:

>>> list(Article.objects.values_list('id', flat=True)) # flat=True will remove the tuples and return the list   
[1, 2, 3, 4, 5, 6]

>>> list(Article.objects.values('id'))
[{'id':1}, {'id':2}, {'id':3}, {'id':4}, {'id':5}, {'id':6}]