Query and order by time difference of a specified time.

[ap....@x76.eu]

Hi.
I am looking for a way to find a row which is closest to a specified
point in time, no matter if the row is before or after.

In plain SQL (using SQLite as example), it's very easy to do;

SELECT *,
abs(
strftime('%s','2015-05-21 23:05:00') - strftime('%s',`created`)
) AS timdif
FROM myapp_posts f ORDER BY timdif LIMIT 10;


The above snippet converts the specified date and field to epoch
seconds, subtracts them and then sorts the query according to the
difference.

Is it possible do this in Django without resorting to raw queries?

Thank you.

[Ketan Bhatt]

Take a look at the `extra` method of the queryset in Django. It allows you to do what you are trying to do by raw SQL.

https://docs.djangoproject.com/en/1.9/ref/models/querysets/#django.db.models.query.QuerySet.extra

Check the above link, the example with `annotate` will be interesting for you.

I think your aim should be to create a new field and then do a `order_by` and `first`.

[Fabio C. Barrionuevo da Luz]

it would probably be better to use a custom "Func"[1] and a custom "Query Expression" [2] than user QuerySet.extra 

[1] https://docs.djangoproject.com/en/1.9/ref/models/database-functions

[2] https://docs.djangoproject.com/en/1.9/ref/models/expressions/

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Fábio C. Barrionuevo da Luz
Palmas - Tocantins - Brasil - América do Sul

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