You should use [aggregates](https://docs.djangoproject.com/en/dev/topics/db/aggregation/#generating-aggregates-for-each-item-in-a-queryset).

    from django.db.models import Count
    User.objects.annotate(page_count=Count(&#39;page&#39;)).filter(page_count__gte=2).count()

In my case, I didn&#39;t use last `.count()` like the [other answer](https://stackoverflow.com/questions/6525771/django-query-related-field-count#6525869) and it also works nice.

    from django.db.models import Count

    User.objects.annotate( our_param=Count(&quot;all_comments&quot;)).filter(our_param__gt=12)

use aggregate() function with django.db.models methods!
this is so useful and not really crushing with other annotation aggregated columns.
*use aggregate() at the last step of calculation, it turns your queryset to dict.

below is my code snippet using them.

    cnt = q.values(&quot;person__year_of_birth&quot;).filter(person__year_of_birth__lte=year_interval_10)\
                   .filter(person__year_of_birth__gt=year_interval_10-10)\
                   .annotate(group_cnt=Count(&quot;visit_occurrence_id&quot;)).aggregate(Sum(&quot;group_cnt&quot;))



i have a table like this:

    name    date         time
    tom | 2011-07-04 | 01:09:52
    tom | 2011-07-04 | 01:09:52
    mad | 2011-07-04 | 02:10:53
    mad | 2009-06-03 | 00:01:01

i want oldest name first: 

    SELECT * 
    ORDER BY date ASC, time ASC 
    GROUP BY name

(-&gt;doesn&#39;t work!)

now it should give me first mad(has earlier date) then tom

but with `GROUP BY name ORDER BY date ASC, time ASC` gives me the newer mad first because it groups before it sorts!

again: the problem is that i can&#39;t sort by date and time before i group because GROUP BY must be before ORDER BY!


ORDER BY date and time BEFORE GROUP BY name in mysql

I created a div tag like this:

    System.Web.UI.HtmlControls.HtmlGenericControl dynDiv = 
        new System.Web.UI.HtmlControls.HtmlGenericControl(&quot;DIV&quot;);

I added style to the div tag like this:

    dynDiv.Style.Add(HtmlTextWriterStyle.BorderStyle, &quot;1px solid #DBE0E4&quot;);
    dynDiv.Style.Add(HtmlTextWriterStyle.Height, &quot;auto&quot;);
    dynDiv.Style.Add(HtmlTextWriterStyle.MarginTop, &quot;5px&quot;);
    dynDiv.Style.Add(HtmlTextWriterStyle.PaddingBottom, &quot;5px&quot;);
    dynDiv.Style.Add(HtmlTextWriterStyle.Width, &quot;682px&quot;);

But I need to control the style of the div tag through an external css file located at folder `~/css/maincss.css`.

How can I apply the css in that file to this div?


how to add css class to html generic control div?

I&#39;ve got an app where users create pages. I want to run a simple DB query that returns how many users have created more than 2 pages.

This is essentially what I want to do, but of course it&#39;s not the right method:

    User.objects.select_related(&#39;page__gte=2&#39;).count()

What am I missing?

Django Query Related Field Count

I've got an app where users create pages. I want to run a simple DB query that returns how many users have created more than 2 pages.
This is essentially what I want to do, but of course it's not the right method:
<pre><code class="hljs language-scss">User.objects.select_related('page__gte=2').count()
</code></pre>
What am I missing?

I&#39;d like to expose some (app-specific) settings to the admin interface, so users can change them comfortably and also not have to restart Django.

How should I go about this?

I checked out the applications on http://djangopackages.com/grids/g/live-setting/ (btw django-constance was the most appealing) but really what all these apps are doing is storing values in a database, providing a web interface to change them, and caching. Aren&#39;t the first two features already built into Django?

The biggest drawbacks I see are that none of the apps are drop-in replacements for the old location of these settings (settings.py), and require me to migrate to their notation, and often add another context processor to access them in templates.

Couldn&#39;t I just do this?

 1. Create a model for my settings (this gives me the various types and validation)
 2. Instantiate one such object to hold my settings (this allows the users to edit them in the admin interface) - I could dump defaults as fixtures like for other models
 3. Wrap settings.py so it makes a database query for my settings - http://www.loose-bits.com/2011/04/extending-django-settings-with-derived.html

From my current, naive point of view the only drawbacks I see would be:

 1. Adding or changing the available settings requires a schema migration (south). - I can live with that.
 2. I have a model with possibly multiple instances but really only need a singleton. - That could actually be a useful feature at some point.
 3. Performance/Caching: Looking at http://code.djangoproject.com/svn/django/trunk/django/conf/ I&#39;d have to put a little bit of cleverness into the settings wrapper and/or model, so that model changes clear or update cached values. - doesn&#39;t seem to be rocket science.
 4. Doing the same in another project would require a similar effort again. - I think a single dictionary constant in settings.py, holding model name(s) and field names for the lookups is all that would differ.

Wouldn&#39;t this be the best of both worlds - runtime admin (with all its perks), database backend, caching, and none of my settings.USED_TO_BE_IN_SETTINGS_DOT_PY would need any changing. Am I missing something?

Changing Django settings at runtime

I have this Model

    summary         = models.TextField()

But I want to have only  4 rows and 15 columns.

Also if I do that do I need to install database again or not.

How can i set the size of rows , columns in textField in Django Models

Is it possible to sort a set of related items in a DJango template?

That is: this code (with HTML tags omitted for clarity):

    {% for event in eventsCollection %}
       {{ event.location }}
       {% for attendee in event.attendee_set.all %}
         {{ attendee.first_name }} {{ attendee.last_name }}
       {% endfor %}
     {% endfor %}

displays ***almost*** exactly want I want.  The only thing I want to change is I the list of attendees to be sorted by last name.  I&#39;ve tried saying something like this:

    {% for event in events %}
       {{ event.location }}
       {% for attendee in event.attendee_set.order_by__last_name %}
         {{ attendee.first_name }} {{ attendee.last_name }}
       {% endfor %}
     {% endfor %}

Alas, the above syntax doesn&#39;t work (it produces an empty list) and neither does any other variation I have thought of (lot&#39;s of syntax errors reported, but no joy).   

I could, of course, produce some kind of array of sorted attendee lists in my view, but that is an ugly and fragile (and did I mention ugly) solution.

Needless to say, but I&#39;ll say it anyway, I have perused the on-line docs and searched Stack Overflow and the archives of django-user without finding anything helpful (ah, if only a query set were a dictionary dictsort would do the job, but it&#39;s not and it doesn&#39;t)

==============================================

Edited to add additional thoughts
after accepting Tawmas&#39;s answer.

-----------------------------------------------
Tawmas addressed the issue exactly as I presented it -- although the solution was not what I expected.  As a result I learned a useful technique that can be used in other situations as well. 

Tom&#39;s answer proposed an approach I had already mentioned in my OP and tentatively rejected as being &quot;ugly&quot;.  

The &quot;ugly&quot; was a gut reaction, and I wanted to clarify what was wrong with it.  In doing so I realized that the reason it was an ugly approach was because I was hung up on the idea of passing a query set to the template to be rendered.   If I relax that requirement, there is an un-ugly approach that should work.  

I haven&#39;t tried this yet, but suppose that rather than passing the queryset, the view code iterated through the query set producing a list of Events, then decorated each Event with a query set for the corresponding attendees which _WAS_ sorted (or filtered, or whatever) in the desired way.   Something like so:
 
    eventCollection = []   
    events = Event.object.[filtered and sorted to taste]
    for event in events:
       event.attendee_list = event.attendee_set.[filtered and sorted to taste]
       eventCollection.append(event)

Now the template becomes:

    {% for event in events %}
       {{ event.location }}
       {% for attendee in event.attendee_list %}
         {{ attendee.first_name }} {{ attendee.last_name }}
       {% endfor %}
     {% endfor %}


The downside is the view has to &quot;actualize&quot; all of the events at once which could be a problem if there were large numbers of events.  Of course one could add pagination, but that complicates the view considerably.  

The upside is the &quot;prepare the data to be displayed&quot; code is in the view where it belongs letting the template focus on formatting the data provided by the view for display. This is right and proper.
       
So my plan is to use Tawmas&#39; technique for large tables and the above technique for small
tables, with the definition of large and small left to the reader (grin.)
        


Sorting related items in a Django template

I want to write a Django query equivalent to this SQL query:

    SELECT * from user where income &gt;= 5000 or income is NULL.

How to construct the Django queryset filter?

    User.objects.filter(income__gte=5000, income=0)

This doesn&#39;t work, because it `AND`s the filters. I want to `OR` the filters to get union of individual querysets.

How to perform OR condition in django queryset?

I have this code

    {% for o in some_list %}

Now I want to do some stuff if I am on an even line. How can I do that?

How do I get odd and even values in a Django for loop template?

Hey i have looked around through some simliar posts here on SO but havent found anything that has solved my problem. I have the following models,

    from django.db import models
    
    class Areas(models.Model):
    
    	name =  models.CharField(max_length = 120)
    	order_in_sidebar_network = models.IntegerField(blank=True, null=True)
    	order_in_section_network = models.IntegerField(blank=True, null=True)
    
    
    	def __unicode__ (self):
    		return self.area_name
    
    	class Meta:
    		verbose_name_plural = &quot;Areas&quot;
    		verbose_name = &quot;Area&quot;
    
    class Countries(models.Model):
    	name = models.CharField(max_length = 120, help_text = &quot;The name of the country&quot;)
    	area = models.ForeignKey(Areas, verbose_name = &#39;Area&#39;)
    	
    	def __unicode__ (self):
    		return self.name
    
    	class Meta:
    		verbose_name_plural = &quot;Countries&quot;
    		verbose_name = &quot;Country&quot;
    		ordering = [&#39;name&#39;]
    
    
    
    class Offices(models.Model):
    	country = models.ForeignKey(Countries, verbose_name = &#39;Country&#39;)
    	name = models.CharField(max_length = 255, help_text = &quot;The name of this office, IE London&quot;)
    	main_office = models.BooleanField(default= False, help_text = &quot;Is this office a key location?&quot;, verbose_name = &quot;Key Location&quot;)
    	address_1 = models.CharField(max_length = 255, null = True, blank = True)
    	address_2 = models.CharField(max_length = 255, null = True, blank = True)
    	address_3 = models.CharField(max_length = 255, null = True, blank = True)
    	city = models.CharField(max_length = 255, null = True, blank = True)
    	postcode = models.CharField(max_length = 20)
    	tel = models.CharField(max_length = 30, null= True, blank = True, help_text = &quot;Optional telephone contact number&quot;)
    	mobile = models.CharField(max_length = 30, null= True, blank = True, help_text = &quot;Optional mobile contact number&quot;)
    	fax = models.CharField(max_length = 30, null= True, blank = True, help_text = &quot;Optional fax contact number&quot;)
    	data_1 = models.CharField(max_length = 255, null = True, blank = True, help_text = &quot;Optional additional data&quot;, verbose_name = &quot;Additional information&quot;)
    	data_2 = models.CharField(max_length = 255, null = True, blank = True, help_text = &quot;Optional additional data&quot;, verbose_name = &quot;Additional information&quot;)
    	
    	class Meta:
    		verbose_name_plural = &quot;Offices&quot;
    		verbose_name = &quot;Office&quot;
    		ordering = [&#39;name&#39;]
    	
    	def __unicode__(self):
    		return self.name
    	
    class OfficeMembers(models.Model):
    	name = models.CharField(max_length = 60, help_text = &quot;Please tell us this person name&quot;)
    	title = models.CharField(max_length = 100, help_text = &quot;The person&#39;s title, IE Managing Director&quot;)
    	email = models.EmailField(max_length = 255, null = True, blank = True, help_text = &quot;Optional email address for this person&quot;)
    	email2 = models.EmailField(max_length = 255, null = True, blank = True, help_text = &quot;Optional second email address for this person&quot;)
    	phone = models.CharField(max_length = 30, null = True, blank  = True, help_text = &quot;Optional contact number for this person&quot;)
    	mobile = models.CharField(max_length = 30, null = True, blank  = True, help_text = &quot;Optional mobile contact number for this person&quot;)
    	office = models.ForeignKey(Offices, null = True)
    	class Meta:
    		verbose_name_plural = &quot;Office Memebers&quot;
    		verbose_name = &quot;Office memebr&quot;
    		ordering = [&#39;name&#39;]
    
    	def __unicode__(self):
    		return self.name

i have the following view set up

    def index(request):
    	
    	cache_key = &quot;world_areas&quot;
    	cache_time = 60
    	
    	world_areas_cache = cache.get(cache_key)
    		
    	#if no cache is set, grab the objects, and set the cache
    	
    	logger.debug(world_areas)
    	if not world_areas_cache:
    		logger.info(&#39;No cache found grabbing objects&#39;)
    		world_areas = Areas.objects.select_related().all()
    		#cache.set(cache_key, world_areas, cache_time)
    		logger.debug(world_areas)
    	else:
    		logger.info(&quot;Getting from cache&quot;)
    		world_areas = world_areas_cache
    		
    	return render_to_response(&#39;network/index.html&#39;, {&#39;world_areas&#39;:world_areas}, context_instance=RequestContext(request))

trying to iterate over the world_areas object like so

    {% for area in world_areas %}
produces a template syntax error

&gt;  &#39;RelatedManager&#39; object is not iterable

Any one got any ideas why this is happeing? really cant seem to get round this! strangley this is working for me in shell :S am i missing something obvious???

Big thanks to anyone able to help!

&#39;RelatedManager&#39; object is not iterable Django

I have a model `Employees` and I would like to have a QuerySet of all rows, but with some specific fields from each row, and not all fields.

I know how to query all rows from the table/model:

    Employees.objects.all()

I would like to know how to select fields for each of the Queryset element. How can I do that?

How to obtain a QuerySet of all rows, with specific fields for each one of them?

I have a model of work orders, with a field for when the work order is required by. To get a list of work orders, with those that are required early, I do this:

`wo = Work_Order.objects.order_by(&#39;dateWORequired&#39;)`

This works nicely, but ONLY if there is actually a value in that field. If there is no required date, then the value is `None`. Then, the list of work orders has all the `None`&#39;s at the top, and then the remaining work orders in proper order. 

How can I get the `None`&#39;s at the bottom?

Django Order By Date, but have &quot;None&quot; at end?

Suppose I have something like this in my models.py:

    class Hipster(models.Model):
      name = CharField(max_length=50)
    
    class Party(models.Model):
      organiser = models.ForeignKey()
      participants = models.ManyToManyField(Profile, related_name=&quot;participants&quot;)


Now in my views.py I would like to do a query which would fetch a party for the user where there are more than 0 participants. 

Something like this maybe:

    user = Hipster.get(pk=1) 
    hip_parties = Party.objects.filter(organiser=user, len(participants) &gt; 0)

What&#39;s the best way of doing it? 


Content Type	Original Author	Original Content on Stackoverflow
Question	Brenden	View Question on Stackoverflow
Solution 1 - Django	Ismail Badawi	View Answer on Stackoverflow
Solution 2 - Django	Yarik	View Answer on Stackoverflow
Solution 3 - Django	wildmental	View Answer on Stackoverflow

Django Query Related Field Count

Django Problem Overview

Django Solutions

Solution 1 - Django

Solution 2 - Django

Solution 3 - Django

how to add css class to html generic control div?

ORDER BY date and time BEFORE GROUP BY name in mysql

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