Hi,
The problem with your approach is the SQL will actually be something like
this:
select <model fields>,
(select id from web_quote WHERE character_length(quote_text) < 30) as val
from <model table>;
That will fail in RDMS like Postgres if there are more than one
"quote_text" with length < 30.
May be you want is something like this:
select <model fields>
from <model table>
where character_length(quote_text) < 30
If that is the case, then you probably will need something like:
return queryset.extra(where=['character_length(quote_text) < 30'])
or even better:
from django.db.models.functions import Length
return
quryset.annotate(quote_len=Length('quote_text')).filter(quote_len__lt=30)
Notice extra() is deprecated.
On Wednesday, March 22, 2017 at 12:25:02 AM UTC-4, kholidfu wrote:
>
> Hi, I'm trying this custom filter query for django admin
>
> return queryset.extra(select = {'val': "select id from web_quote WHERE
> character_length(quote_text) < 30"})
>
>
> and I got something like this:
>
> Programming error: more than one row returned by a subquery used as an
> expression
>
> Basically I'm trying to filter quote_text column which length of the
> string less than 30...
>
> Any ideas?
>
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