Question

I have two models

class Weather(model.model):

        region = models.ForeignKey(Region)
        district = models.ForeignKey(District)
        temp_max = models.IntegerField(blank=True, null=True, verbose_name='Max temperature (C)')
        temp_min = models.IntegerField(blank=True, null=True, verbose_name='Min temperature (C)')

and

class Plan(model.model):
    name = tinymce_models.HTMLField(blank=True, null=True)
    region = models.ForeignKey(Region)
    district = models.ForeignKey(District)

Provided for every region and district have unique row.
I want to combine the result so that i can get all the columns of both tables

These two Models are not related to each other.
‘
I need to make the join like

join weather w on w.region = A.region and w.distric = A.district

so that result contains all the columns in everyobject like

obj.temp_max etc

Answer 1

w = Weather.objects.get(pk=1)
w.region.plan.name
w.district.plan.name
w.temp_max
w.temp_min

w.region is the linked region row, so any attribute in the region model can be accessed through it. So if your region model had a name, you would do w.region.name, and its the same with w.district.

w.region.plan is the row in the plan table that has a foreign key to the region row that is linked to the weather object with the primary key of 1; w.district.plan works the same way.

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Also the data i have to display is for the plans . so i want to go
from plan to weather . not from weather to plan. i don’t think i can
go plan.region.weather.temp_max because there will be many rows for
one region and i want to filter on comination of region and district

p = Plan.objects.get(pk=1) # get a Plan
p.region.weather_set.all() # all "weathers" for the region for this plan
p.district.weather_set.all() # all "weathers" for the district for this plan

To filter:

plans = Plan.objects.filter(region__name='Region 1') # all plans for that region
for plan in plans:
   region_weather = plan.region.weather_set.all()
   district_weather = plan.district.weather_set.all()

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if i have the more than one row , is there any way to aggregate that
e,g temperature . ie i have two weather enteries for same region and
district and i want the avg

Yes, read the documentation on aggregation.