Django Count rows with duplicate values

Question

I am working on counting rows with duplicate values in a django Model and running into a little hitch. I have looked at this question Django Select Rows with duplicate Values

and the solution is perfect. But my question is, What if I want to Count the rows and group them according to: Name of the duplicated row, and how many times it has been duplicated, instead of just displaying the name of the repeated rows.

my code so far:

views.py

dupes = Application.objects.values('school_name').annotate(Count('id')).filter(id__count__gt=1)
query = Application.objects.filter(school_name__in=[item['school_name'] for item in dupes])

The query variable returns a queryset with the Applications that have duplicate values for the field school_name while this line:

repeated_names = Application.objects.values('school_name', 'category', ).annotate(Count('id')).order_by().filter(id__count__gt=1)

returns a list of the duplicated school names.

What I expect is something like:

(school_name=school_name_1, count=2), (school_name=school_name_2, count=3).. etc.

You obviously are rendering this data in front end right?

ans2human
– ans2human

2019-02-19 07:48:09 +00:00
Commented Feb 19, 2019 at 7:48 — ans2human
– ans2human, Commented Feb 19, 2019 at 7:48
@ans2human yes, that's right

Abedy
– Abedy

2019-02-19 07:50:02 +00:00
Commented Feb 19, 2019 at 7:50 — Abedy
– Abedy, Commented Feb 19, 2019 at 7:50

ans2human · Accepted Answer · 2019-02-19 09:25:51Z

3

Try this:

In your Views.py use this queryset:

repeated_names = Application.objects.values('school_name', 'category').annotate(Count('id')).order_by().filter(id__count__gt=0)   # <--- gt 0 will get all the objects having occurred in DB i.e is greater than 0

gt 0 will get all the objects having occurred in DB i.e is greater than 0

In your Template:

 {% for c in repeated_names %}

 <ul>

 <li>{{c.school_name}}</li>

 <li>{{c.id__count}}</li>

 <li>{{c.category}}</li>


</ul>

{% endfor %}

edited Feb 19, 2019 at 9:25

answered Feb 19, 2019 at 7:57

ans2human

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11 Comments

Abedy Over a year ago

This worked with the client_ ommitted. But is there no way I way I can do this in the views?

Abedy Over a year ago

And also, how can I get access to the values of other fields on the same row?

ans2human Over a year ago

@Abedy Yes Updated the answer, You're already doing it in the views. To get rest of the fields data i have updated the query. Please check

Abedy Over a year ago

The updated query seems to have a bug. It only displays one item.

ans2human Over a year ago

@Abedy update the question with query you are using now and also the error you're getting. I'll check.

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