Django ORM Select Column From Two Model or More - django

Question

I want select column with django orm from two model or more.
SELECT nim, k.kode, s.nama, sks, nilai, th_ajaran FROM mahasiswa_khs k, mata_kuliah_si s WHERE k.kode = s.kode AND nim = %s
This is my code
khs = Khs.objects.filter(nim=nim).values_list('kode').union(SI.objects.all().values_list('kode'))
But, went I call in template it's didn't show
It's my template :
{% for khs in khs %}
<tr>
<td>{{forloop.counter}}</td>
<td>{{khs.kode}}</td>
<td>{{khs.nama}}</td>
<td>{{khs.sks}}</td>
<td class="vertical-align-mid">{{khs.nilai}}</td>
<th>{{khs.th_ajaran}}</th>
</tr>
{% endfor %}
And the view :
khs = Khs.objects.filter(nim=nim).union(SI.objects.all().values_list('kode'))
context ={
'khs' : khs,
}
return render(request, 'mahasiswa/mahasiswa.html',context)

Answer 1

When you use .values_list or .values you're telling the ORM to only select those columns. As per the docs:
This is similar to values() except that instead of returning
dictionaries, it returns tuples when iterated over. Each tuple
contains the value from the respective field or expression passed into
the values_list() call — so the first item is the first field, etc.
For example:
from django.db.models.functions import Lower
Entry.objects.values_list('id', Lower('headline')) <QuerySet [(1, 'first entry'), ...]>```
Since you're using values_list, this means you're pulling out a dataset that looks like: [('kode_value_1',), ('kode_value_2', ), ...]. In your template you'd use:
{% for values in khs %}
{{ values.0 }}
{% endfor %}
In order to pull additional fields such as nama, you'd need to adjust your queryset:
khs = (
Khs.objects.filter(nim=nim)
.values_list('kode', 'nama')
.union(SI.objects.all().values_list('kode', 'nama'))
)
Then in your template you'd have:
{% for values in khs %}
kode: {{ values.0 }}
nama: {{ values.1}}
{% endfor %}
If you want to use the field names, then you should use values() instead of values_list() so that your template tag would be {{ values.kode }}
In the case that SI does not have the nama field, you can make an annotation that sets out a dummy value so the union can occur.
from django.db.models import Value, CharField
khs = (
Khs.objects.filter(nim=nim)
.values_list('kode', 'nama')
.union(
SI.objects
.annotate(nama=Value(None, output_field=CharField()))
.values_list('kode', 'nama')
)
)
I took a guess that nama is a CharField. You may need to change that as your data model requires. The annotation approach could also work to avoid the use of .values_list altogether if you'd like.