What about queryset extras? They do not break ORM and can be further filtered (vs RawSQL)

from django.db.models import Q

Track.objects.filter(
  # work around to force left outer join
  Q(trackhastag__isnull=True) | Q(trackhastag__isnull=False)
).extra(
    # where parameters are “AND”ed to any other search criteria
    # thus we need to account for NULL
    where=[
        '"app_trackhastag"."id" <> %s or "app_trackhastag"."id" is NULL'
    ],
    params=[1],
)

produces this somewhat convoluted query:

SELECT "app_track"."id", "app_track"."title", "app_track"."artist"
FROM "app_track"
LEFT OUTER JOIN "app_trackhastag"
ON ("app_track"."id" = "app_trackhastag"."track_id")
WHERE (
    ("app_trackhastag"."id" IS NULL OR "app_trackhastag"."id" IS NOT NULL) AND
    ("app_trackhastag"."id" <> 1 or "app_trackhastag"."id" is NULL)
)

Rationale

Step 1

One straight forward way to have a left outer join with queryset is the following:

Track.objects.filter(trackhastag__isnull=True)

which gives:

SELECT "app_track"."id", "app_track"."title", "app_track"."artist"
FROM "app_track"
LEFT OUTER JOIN "app_trackhastag"
ON ("app_track"."id" = "app_trackhastag"."track_id")
WHERE "app_trackhastag"."id" IS NULL

Step 2

Realize that once step 1 is done (we have a left outer join), we can leverage
queryset’s extra:

Track.objects.filter(
    trackhastag__isnull=True
).extra(
    where=['"app_trackhastag"."id" <> %s'],
    params=[1],
)

which gives:

SELECT "app_track"."id", "app_track"."title", "app_track"."artist"
FROM "app_track"
LEFT OUTER JOIN "app_trackhastag"
ON ("app_track"."id" = "app_trackhastag"."track_id")
WHERE (
    "app_trackhastag"."id" IS NULL AND
    ("app_trackhastag"."id" <> 1)
)

Step 3

Playing around extra limitations (All where parameters are “AND”ed to any other search criteria) to come up with final solution above.

Using filters is better than exclude… because wit exclude they will get the entire query first and only than excluding the itens you dont want, while filter get only what you want Like you said Track.objects.filter(trackhastagfoo__isnull=True) is better than Exclude one.

Suggestion: You trying to manually do one ManyToMany Relations, as Mohammad said, why you dont try use ManyToManyField? is more easy to use

Maybe this answer your question: Django Left Outer Join

Enric, why you did not use many to many relation

class Track(models.Model):
    title = models.TextField()
    artist = models.TextField()
    tags = models.ManyToManyField(Tag)

class Tag(models.Model):
    name = models.CharField(max_length=50)

And for your question

Track.objects.filter(~Q(tags__id=1))