how to perform Rank query in Django - sql

Question

I am stuck at this point and this query seems a bit tricky to me
so basically i am getting data from devices in periodic intervals 'lets say 3 hours'
But every device is sending data twice on every interval(3 hours), i am required to extract device data that is send last(in intervals)
"date": "2021-11-28",
"time": "12 : 35",
"meter": "70F8E7FFFE10C495",
"dr": 3,
"date_received": "2021-11-28T18:05:20.473430+05:30",
},
{
"id": 2,
"date": "2021-11-28",
"time": "12 : 37",
"meter": "70F8E7FFFE10C459",
"date_received": "2021-11-28T18:07:09.980403+05:30",
},
{
"id": 3,
"date": "2021-11-28",
"time": "12 : 37",
"meter": "70F8E7FFFE10C459", <---- this occurrence only
"dr": 3,
"date_received": "2021-11-28T18:07:11.533388+05:30",
},
{
"id": 4,
"date": "2021-11-28",
"time": "12 : 50",
"meter": "70F8E7FFFE10C463",
"date_received": "2021-11-28T18:20:44.197284+05:30",
},
{
"id": 5,
"date": "2021-11-28",
"time": "12 : 56",
"meter": "70F8E7FFFE10C47D",
"date_received": "2021-11-28T18:26:43.221316+05:30",
},
{
"id": 6,
"date": "2021-11-28",
"time": "12 : 56",
"meter": "70F8E7FFFE10C47D", <---- only want to get this occurrence in similar manner
"date_received": "2021-11-28T18:26:44.925292+05:30",
},
So if device : 70F8E7FFFE10C459 sends data twice i want to retrieve only last sent data , and this needs obj in queryset , i was told about RANK concept don't understand how to apply that here
In general i just want to know the query to apply, raw query will also work
class MeterData(models.Model):
meter = models.ForeignKey('dashboard.Meter',on_delete=models.SET_NULL,null=True)
customer = models.ForeignKey('Customer',on_delete=models.SET_NULL,null=True,blank=True)
battery = models.CharField(max_length=40,null=True,blank=True)
crc_status = models.CharField(max_length=43,null=True,blank=True)
Pulse_count = models.IntegerField(null=True,blank=False)
status_data = models.CharField(max_length=50,blank=True,null=True)
status_magnet_temper = models.BooleanField(default=False)
meter_reading = models.CharField(max_length=50,null=True,blank=True)
status_switch_temper = models.BooleanField(default=False)
status_voltage_level = models.CharField(max_length=10,null=True,blank=True)
uplink_type = models.CharField(max_length=50,null=True,blank=True)
confirmed_uplink = models.BooleanField(max_length=50,null=True,blank=True)
tx_info_frequency = models.CharField(max_length=50,null=True,blank=True)
dr = models.IntegerField(null=True,blank=True)
date_received = models.DateTimeField(auto_now_add=True,null=True)

Answer 1

It doesn't work on Sqlite
I think the following query is the correct answer.
MeterData.objects.filter(put_your_filters_here).order_by('-date_received').distinct('customer_id')
For SQLite DB use the below query:
from django.db.models import Subquery, OuterRef
distinct_subquery = Subquery(MeterData.objects.filter(put_your_filters_here, customer_id=OuterRef('customer_id')).order_by('-date_received').values('id')[:1])
MeterData.objects.filter(put_your_filters_here, id__in=distinct_subquery).order_by('-date_received')
if it doesn't work let me know.