"&" and "|" vs "and" and "or" for "AND" and "OR" operators in Django

Question

I have Blog model below. *I use Django 3.2.16 and PostgreSQL:

# "store/models.py"

from django.db import models

class Blog(models.Model):
    post = models.TextField()
    
    def __str__(self):
        return self.post

Then, store_blog table has 2 rows below:

`store_blog` table:

id	post
1	Python is popular and simple.
2	Java is popular and complex.

Then, when running the filter() code using & or Q() and & or using and or Q() and and in test() view as shown below:

# "store/views.py"

from .models import Blog
from django.db.models import Q
from django.http import HttpResponse

def test(request):

    # With "&"
                                                     # ↓ Here
    qs = Blog.objects.filter(post__contains="popular") & \
         Blog.objects.filter(post__contains="simple")
    print(qs)

    # With "Q()" and "&"
                           # ↓ Here                    # ↓ Here
    qs = Blog.objects.filter(Q(post__contains="popular") & 
            　　　　　　　　　　Q(post__contains="simple"))
    print(qs)              # ↑ Here

    # With "and"
                                                      # ↓ Here
    qs = Blog.objects.filter(post__contains="popular") and \
         Blog.objects.filter(post__contains="simple")
    print(qs)

    # With "Q()" and "and"
                           # ↓ Here                     # ↓ Here
    qs = Blog.objects.filter(Q(post__contains="popular") and 
            　　　　　　　　　　Q(post__contains="simple"))
    print(qs)              # ↑ Here

    return HttpResponse("Test")

I got the same result below:

<QuerySet [<Blog: Python is popular and simple.>]> # With "&"
<QuerySet [<Blog: Python is popular and simple.>]> # With "Q()" and "&"
<QuerySet [<Blog: Python is popular and simple.>]> # With "and"
<QuerySet [<Blog: Python is popular and simple.>]> # With "Q()" and "and"
[22/Dec/2022 16:04:45] "GET /store/test/ HTTP/1.1" 200 9

And, when running the filter() code using | or Q() and | or using or or Q() and or in test() view as shown below:

# "store/views.py"

from .models import Blog
from django.db.models import Q
from django.http import HttpResponse

def test(request):

    # With "|"
                                                     # ↓ Here
    qs = Blog.objects.filter(post__contains="popular") | \
         Blog.objects.filter(post__contains="simple")
    print(qs)

    # With "Q()" and "|"
                           # ↓ Here                    # ↓ Here
    qs = Blog.objects.filter(Q(post__contains="popular") | 
                             Q(post__contains="simple"))
    print(qs)              # ↑ Here

    # With "or"
                                                     # ↓ Here
    qs = Blog.objects.filter(post__contains="popular") or \
         Blog.objects.filter(post__contains="simple")
    print(qs)

    # With "Q()" and "or"
                           # ↓ Here                    # ↓ Here
    qs = Blog.objects.filter(Q(post__contains="popular") or 
                             Q(post__contains="simple"))
    print(qs)              # ↑ Here

    return HttpResponse("Test")

I got the same result below:

<QuerySet [<Blog: Python is popular and simple.>, <Blog: Java is popular and complex.>]> # With "|"
<QuerySet [<Blog: Python is popular and simple.>, <Blog: Java is popular and complex.>]> # With "Q()" and "|"
<QuerySet [<Blog: Python is popular and simple.>, <Blog: Java is popular and complex.>]> # With "or"
<QuerySet [<Blog: Python is popular and simple.>, <Blog: Java is popular and complex.>]> # With "Q()" and "or"
[22/Dec/2022 16:20:27] "GET /store/test/ HTTP/1.1" 200 9

So, are there any differences between & and and and | and or for AND and OR operators in Django?

score 2 · Answer 1 · answered Dec 22 '22 at 08:01

Your test data is quite insufficient for this test since both rows contain popular. (IOW, anything that would find popular is equivalent to Blog.objects.all().)

Anyway, boolean or and and don't work correctly here (since they're just doing boolean evaluation), but you're just not noticing because of the above.
You need to use the "bitwise" | / & / ^ operators, as documented. ("bitwise" in quotes, since the Q class overloads the operators to not be bitwise at all.)

For proof, let's look at the Qs in isolation, without querying anything...

>>> from django.db.models import Q
>>> pop = Q(post__contains="popular")
<Q: (AND: ('post__contains', 'popular'))>
>>> sim = Q(post__contains="simple")
<Q: (AND: ('post__contains', 'simple'))>
>>> pop and sim
<Q: (AND: ('post__contains', 'simple'))>
# ^ incorrect; evaluates to `sim`
>>> pop & sim
<Q: (AND: ('post__contains', 'popular'), ('post__contains', 'simple'))>
# ^ correct: combines the two q:s with `and`
>>> pop or sim
<Q: (AND: ('post__contains', 'popular'))>
# ^ incorrect; evaluates to `pop`
>>> pop | sim
<Q: (OR: ('post__contains', 'popular'), ('post__contains', 'simple'))>
# ^ correct: combines the two q:s with `or`

score 0 · Answer 2 · answered Dec 23 '22 at 04:13

When running the filter() code using & or Q() and & or using and or Q() and and in test() view as shown below:

# "store/views.py"

from .models import Blog
from django.db.models import Q
from django.http import HttpResponse

def test(request):

    # With "&"
                                                     # ↓ Here
    qs = Blog.objects.filter(post__contains="popular") & \
         Blog.objects.filter(post__contains="simple")
    print(qs)

    # With "Q()" and "&"
                           # ↓ Here                    # ↓ Here
    qs = Blog.objects.filter(Q(post__contains="popular") & 
            　　　　　　　　　　Q(post__contains="simple"))
    print(qs)              # ↑ Here

    # With "and"
                                                      # ↓ Here
    qs = Blog.objects.filter(post__contains="popular") and \
         Blog.objects.filter(post__contains="simple")
    print(qs)

    # With "Q()" and "and"
                           # ↓ Here                     # ↓ Here
    qs = Blog.objects.filter(Q(post__contains="popular") and 
            　　　　　　　　　　Q(post__contains="simple"))
    print(qs)              # ↑ Here

    return HttpResponse("Test")

& or Q() and & can run AND operators according to the query logs of PostgreSQL as shown below. *You can check on PostgreSQL, how to log queries with transaction queries such as "BEGIN" and "COMMIT":

And, when running the filter() code using | or Q() and | or using or or Q() and or in test() view as shown below:

# "store/views.py"

from .models import Blog
from django.db.models import Q
from django.http import HttpResponse

def test(request):

    # With "|"
                                                     # ↓ Here
    qs = Blog.objects.filter(post__contains="popular") | \
         Blog.objects.filter(post__contains="simple")
    print(qs)

    # With "Q()" and "|"
                           # ↓ Here                    # ↓ Here
    qs = Blog.objects.filter(Q(post__contains="popular") | 
                             Q(post__contains="simple"))
    print(qs)              # ↑ Here

    # With "or"
                                                     # ↓ Here
    qs = Blog.objects.filter(post__contains="popular") or \
         Blog.objects.filter(post__contains="simple")
    print(qs)

    # With "Q()" and "or"
                           # ↓ Here                    # ↓ Here
    qs = Blog.objects.filter(Q(post__contains="popular") or 
                             Q(post__contains="simple"))
    print(qs)              # ↑ Here

    return HttpResponse("Test")

| or Q() and | can run OR operators according to the query logs of PostgreSQL as shown below:

"&" and "|" vs "and" and "or" for "AND" and "OR" operators in Django

`store_blog` table:

2 Answers2

Linked

"&" and "|" vs "and" and "or" for "AND" and "OR" operators in Django

store_blog table:

2 Answers2

Linked

`store_blog` table: