Re: union of two QuerySets

[Robin Pedersen]

There might be situations where you already have a couple of querysets, and 
want to combine them, or for DRYness it might be an idea to create 
functions that return querysets, and combine the results:

combined = self.get_some() | self.get_others()

And querysets are lazily executed, so unless you actually use the results 
of the individual querysets, only one combined query is executed, just like 
in your example.

On Wednesday, August 1, 2012 5:28:49 PM UTC+2, Àlex Pérez wrote:
>
> Hi,
>
> it's better  Person.objects.filter(models.Q(first_**name__startswith='mic'), 
> models.Q(first_**name__startswith='joh'))
> (only one query...)
>
>
> 2012/8/1 Robin Pedersen <robinpe...@gmail.com>
>
>> On Monday, December 11, 2006 4:37:25 AM UTC+1, Rares Vernica wrote:
>>>
>>> Hi,
>>>
>>> What is a way to get the union of two QuerySets?
>>>
>>> Something like:
>>>
>>> In [6]: a = Person.objects.filter(first_**name__startswith='mic')
>>>
>>> In [7]: b = Person.objects.filter(first_**name__startswith='joh')
>>>
>>> In [8]: a + b
>>>
>>> Thanks a lot,
>>> Ray
>>>
>>
>> Try:
>>
>> a | b
>>
>>  
>>
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>
>
>
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Re: union of two QuerySets

[akaariai]

On 1 elo, 19:15, Tim Chase  wrote:
> On 08/01/12 10:28, lex P rez wrote:
>
> > Hi,
>
> > it's better  Person.objects.filter(models.Q(first_**name__startswith='mic'),
> > models.Q(first_**name__startswith='joh'))
> > (only one query...)
>
> I'm pretty sure this will get you the intersection (it uses AND)
> rather than the union (which would be using OR).  So I think you want
>
>  from django.db.models import Q
>  Person.objects.filter(
>    Q(first_name__startswith="mic") |
>    Q(first_name__startswith="joh")
>    )
>
> using the "|" (OR) operator to join the two Q objects.
>
> -tkc
>
> For reference, you can read at
>
> https://docs.djangoproject.com/en/dev/ref/models/querysets/#django.db...
>
> https://docs.djangoproject.com/en/dev/topics/db/queries/#complex-look...

As stated earlier the correct way to combine two existing querysets is
to do: combined = qs1 | qs2.

There are some limitations to what kind of querysets will work, but
for plain querysets which have just filers applied things should just
work.

 - Anssi

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Re: union of two QuerySets

[Tim Chase]

On 08/01/12 10:28, Àlex Pérez wrote:
> Hi,
> 
> it's better  Person.objects.filter(models.Q(first_**name__startswith='mic'),
> models.Q(first_**name__startswith='joh'))
> (only one query...)

I'm pretty sure this will get you the intersection (it uses AND)
rather than the union (which would be using OR).  So I think you want

 from django.db.models import Q
 Person.objects.filter(
   Q(first_name__startswith="mic") |
   Q(first_name__startswith="joh")
   )

using the "|" (OR) operator to join the two Q objects.

-tkc


For reference, you can read at

https://docs.djangoproject.com/en/dev/ref/models/querysets/#django.db.models.query.QuerySet.filter

https://docs.djangoproject.com/en/dev/topics/db/queries/#complex-lookups-with-q-objects


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Re: union of two QuerySets

[Àlex Pérez]

Hi,

it's better  Person.objects.filter(models.Q(first_**name__startswith='mic'),
models.Q(first_**name__startswith='joh'))
(only one query...)


2012/8/1 Robin Pedersen <robinpe...@gmail.com>

> On Monday, December 11, 2006 4:37:25 AM UTC+1, Rares Vernica wrote:
>>
>> Hi,
>>
>> What is a way to get the union of two QuerySets?
>>
>> Something like:
>>
>> In [6]: a = Person.objects.filter(first_**name__startswith='mic')
>>
>> In [7]: b = Person.objects.filter(first_**name__startswith='joh')
>>
>> In [8]: a + b
>>
>> Thanks a lot,
>> Ray
>>
>
> Try:
>
> a | b
>
>
>
> --
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-- 
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alex.pe...@bebabum.com

 *bebabum* be successful

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08008 Barcelona
http://www.bebabum.com
http://www.facebook.com/bebabum
http://twitter.com/bebabum

This message is intended exclusively for its addressee and may contain
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If you are not the intended recipient you are hereby notified that any
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prohibited by law.

Este mensaje se dirige exclusivamente a su destinatario y puede contener
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indicado,
queda notificado que la utilización, divulgación y/o copia sin autorización
está prohibida en virtud de la legislación vigente.

Le informamos que los datos personales que facilite/ha facilitado pasarán a
formar parte de un fichero responsabilidad de bebabum, S.L. y que tiene
por finalidad gestionar las relaciones con usted.
Tiene derecho al acceso, rectificación cancelación y oposición en nuestra
oficina ubicada en c/ Còrsega 301-303, Àtic 2 de Barcelona o a la dirección
de e-mail l...@bebabum.com

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Re: union of two QuerySets

[Robin Pedersen]

On Monday, December 11, 2006 4:37:25 AM UTC+1, Rares Vernica wrote:
>
> Hi,
>
> What is a way to get the union of two QuerySets?
>
> Something like:
>
> In [6]: a = Person.objects.filter(first_name__startswith='mic')
>
> In [7]: b = Person.objects.filter(first_name__startswith='joh')
>
> In [8]: a + b
>
> Thanks a lot,
> Ray
>

Try:

a | b

 

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Re: Union of two querysets?

[Nick Booker]

Yes you can do a union.  Use the "|" (pipe) operator.

 union = queryset1 | queryset2

or you can replace queryset1 with the union as follows:

 queryset1 |= queryset2

Nick

On 16/02/10 02:39, rebus_ wrote:

On 16 February 2010 03:28, ydjango  wrote:

I have two query sets with two different where clauses on same table
and same columns in select. Is it possible to have their union.

I tried qryset = qryset1 + qryset2
  It gave me - "+ unsupported operand"

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Perhaps you could try to use OR lookup using Q objects?

http://docs.djangoproject.com/en/dev/topics/db/queries/#complex-lookups-with-q-objects



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Re: Union of two querysets?

[rebus_]

On 16 February 2010 03:28, ydjango  wrote:
> I have two query sets with two different where clauses on same table
> and same columns in select. Is it possible to have their union.
>
> I tried qryset = qryset1 + qryset2
>  It gave me - "+ unsupported operand"
>
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>
>

Perhaps you could try to use OR lookup using Q objects?

http://docs.djangoproject.com/en/dev/topics/db/queries/#complex-lookups-with-q-objects

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Union of two querysets?

[ydjango]

I have two query sets with two different where clauses on same table
and same columns in select. Is it possible to have their union.

I tried qryset = qryset1 + qryset2
 It gave me - "+ unsupported operand"

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Re: union of two QuerySets

[Honza Král]

if you want a true union, use chain from itertools on the two querysets...

On 12/11/06, Jeremy Dunck <[EMAIL PROTECTED]> wrote:
>
> On 12/11/06, Rares Vernica <[EMAIL PROTECTED]> wrote:
> >
> > Hi,
> >
> > I know the Q way, but actually the filter contains already a lot of Qs.
> >
> > I am looking for a way to combine "a" and "b" without going into their
> > filters.
>
> QuerySets are lazy.  There's no downside to combining two
> arbitrarily-complex querysets either before or after the filter
> call(s).
>
> >
>


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E-Mail: [EMAIL PROTECTED]
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Phone:  +420 606 678585

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Re: union of two QuerySets

[Jeremy Dunck]

On 12/11/06, Rares Vernica <[EMAIL PROTECTED]> wrote:
>
> Hi,
>
> I know the Q way, but actually the filter contains already a lot of Qs.
>
> I am looking for a way to combine "a" and "b" without going into their
> filters.

QuerySets are lazy.  There's no downside to combining two
arbitrarily-complex querysets either before or after the filter
call(s).

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Re: union of two QuerySets

[Rares Vernica]

Hi,

I know the Q way, but actually the filter contains already a lot of Qs.

I am looking for a way to combine "a" and "b" without going into their 
filters.

Thanks

Jacob Kaplan-Moss wrote:
> On 12/10/06 9:37 PM, Rares Vernica wrote:
>> What is a way to get the union of two QuerySets?
> 
> See 
> http://www.djangoproject.com/documentation/db_api/#complex-lookups-with-q-objects.
> 
>> In [6]: a = Person.objects.filter(first_name__startswith='mic')
>>
>> In [7]: b = Person.objects.filter(first_name__startswith='joh')
> 
> Try::
> 
>   >>> Person.objects.filter(
>   ... Q(first_name__startswith="mic") |
>   ... Q(first_name__startswit="joh")
>   ... )
> 
> Jacob
> 
> > 
> 


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Re: union of two QuerySets

[Jacob Kaplan-Moss]

On 12/10/06 9:37 PM, Rares Vernica wrote:
> What is a way to get the union of two QuerySets?

See 
http://www.djangoproject.com/documentation/db_api/#complex-lookups-with-q-objects.

> In [6]: a = Person.objects.filter(first_name__startswith='mic')
> 
> In [7]: b = Person.objects.filter(first_name__startswith='joh')

Try::

>>> Person.objects.filter(
... Q(first_name__startswith="mic") |
... Q(first_name__startswit="joh")
... )

Jacob

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