Queries in query set group in to one query using Django

Question

I have a query set like the below.

<QuerySet[{'user':'xyz','id':12,'home':'qwe','mobile':1234}, 
          {'user':'xyz','id':12,'home':'qwe','mobile':4321}, 
          {'user':'abc','id':13,'home':'def','mobile':1233}, 
          {'user':'abc','id':13,'home':'def','mobile':1555},]>

This QuerySet is returned by django using

users.objects.all()

For Each query in the query set, I'm drawing a user table in the front-end which shows the details of users. If the same 'user' registers with two 'mobile' numbers, it is showed as two rows in the table instead of one. My goal is to display two numbers in the same row instead of creating two rows.

I have thought of two possible solutions which are below:

Solution 1: I have thought of merging the two queries into one if the 'user' value matches in both the queries. For this we need to make lot of checks using conditional statements which works slowly when lot of users are there.

Solution 2: I have searched on Google and came up with Group By Django, but it is not working. I have tried below

query = users.objects.all().query
query.group_by = ['mobile']
results = QuerySet(query=query, model=users)  

Please provide a way so that two queries can be clubbed into one based on 'user' and after clubbing 'mobile' should contain two values.

Edit: I will pass this query set to a template via view where the table is being drawn. At present, for each query, one row is the in table. Since the above query set has four queries, we will have four rows. But I want to display the information in just two rows since the 'id' and 'user' are same. Code for template is below:

{% if users %}
    {% for user in users %}
        {% for k,v in required_keys.items %}
            <td>{{ user | get_item:k }}
        {% endfor %}
    {% endfor %}
{% endif %}    

Required key is an dictionary which contains the keys which are used to display in table. Example:

Required_keys = {
    'User Name':user,
    'Contact':mobile,
    'Address':home,
} 

The get item is a function which gets the value when key is passed.

def get_item(dictionery,key):
    return dictionery.get(key)

Edit 2: I have tried for a solution and it's not a full solution but it partially solves the problem. The solution perfectly works with one user. However if there are many users, the solution doesn't work. See below for example:

# input query set to the function which partially solves the problem 
<QuerySet[{'user':'xyz','id':12,'home':'qwe','mobile':1234}, 
      {'user':'xyz','id':12,'home':'qwe','mobile':4321},]> 

# Now our team has written a function which gives the following output
<QuerySet[{'user':'xyz','id':12,'home':'qwe','mobile':1234,4321},]>

But if there are more than one user, the output is same as input, it doesn't club the queries. See the function below:

def merge_values(cls,values):
    import itertools
    grouped_results = itertools.groupby(values,key=lambda x:x['id'])
    merged_values = []
    for k,g in grouped_results:
        groups=list(g)
        merged_value = {}
        for group in groups:
            for key, val in group.iteritems():
                if not merged_value.get(key):
                    merged_value[key] = val
                elif val != merged_value[key]:
                    if isinstance(merged_value[key], list):
                        if val not in merged_value[key]:
                            merged_value[key].append(val)
                        else:
                            old_val = merged_value[key]
                            merged_value[key] = [old_value, val]
        merged_values.append(merged_value)
    return merged_values

The values parameter for the function is the whole query set. But this function works if there is only one user in query set as mentioned above. But if there are multiple users, it fails.

Edit 3: I have found why above function won't work for multiple users(don't know whether this is correct). The input query set to the function (for one user) is

<QuerySet[{'user':'xyz','id':12,'home':'qwe','mobile':1234}, 
      {'user':'xyz','id':12,'home':'qwe','mobile':4321},]>

Since the two user queries are one after another, they are clubbed. But if there are multiple users, the query set passed to the function is

<QuerySet[{'user':'xyz','id':12,'home':'qwe','mobile':1234}, 
      {'user':'xyz','id':13,'home':'qwe','mobile':4321}, 
      {'user':'abc','id':12,'home':'def','mobile':1233}, 
      {'user':'abc','id':13,'home':'def','mobile':1555},]>

In the above query set, the user with same id are not one after another, so the function failed to get desired output.

Answer 1

You can use the function which you have written, only change is required is need to order the values based on id. So before taking the values from the objects, order_by('id'), then take your required values and pass it to your function to merge the values.

Eg.

query_set = Mymodel.objects.filter(name='Required').order_by('id')
values = query_set.values('id', 'field1', 'field2')
merged_values = merge_values(values)

Answer 2

As a start, what would be helpful is to organise your models better. You have user information duplicated in your user model. If a you know that a user has multiple mobile numbers, it may be better to create a separate model for that:

class Mobile(models.Model)
    number = models.IntegerField()
    user = models.ForeignKey(User)

Then, when you are make a query and you want to get all the mobile numbers, you would first get all the users using users = User.objects.all() in your view, then in your template:

{% for user in users %}
    {% for mobile in user.mobile_set.all %}
        <td>{{ user }}</td>
        <td>{{ mobile.number }}</td>
    {% endfor %}
{% endfor %}

As a side note, I feel it's better practice to name your models as a singular (User instead of Users)