Re: coalesce(json_agg [..] filter where [..], '[]' in left join returning null
| От | Stefan Houtzager |
|---|---|
| Тема | Re: coalesce(json_agg [..] filter where [..], '[]' in left join returning null |
| Дата | |
| Msg-id | CANJtTDkecQ0h1rYrSQc_g=2E6mdAdC8citm-CLA8z4_yhmgvjw@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: coalesce(json_agg [..] filter where [..], '[]' in left join returning null ("David G. Johnston" <david.g.johnston@gmail.com>) |
| Список | pgsql-novice |
On Wed, Jan 6, 2021 at 5:38 PM David G. Johnston <david.g.johnston@gmail.com> wrote:
Please don't top-post here.The general concept should work. You may at least wish to experiment in a simple query to get the feel for the mechanics. With respect to this query I'd probably need to have a working query to play with (and time) to give a more precise answer.David J.
Thanks David,
I do not get what you suggest working within the left-join. What does work is the following:
select json_agg(_)
from (
select
vc.id,
vc.descr,
vc.expense,
vc.version,
(select coalesce(json_agg(_), '[]')
from (
select
vp.percentage,
vp.version,
json_build_object(
'lower', lower(vp.validity),
'upper', upper(vp.validity),
'lower_inc', lower_inc(vp.validity),
'upper_inc', upper_inc(vp.validity)
) validity
from vat_percentage vp
where vp.vatcat_id = vc.id
) _
) as percentages
from vat_cat vc
group by vc.id
) _
from (
select
vc.id,
vc.descr,
vc.expense,
vc.version,
(select coalesce(json_agg(_), '[]')
from (
select
vp.percentage,
vp.version,
json_build_object(
'lower', lower(vp.validity),
'upper', upper(vp.validity),
'lower_inc', lower_inc(vp.validity),
'upper_inc', upper_inc(vp.validity)
) validity
from vat_percentage vp
where vp.vatcat_id = vc.id
) _
) as percentages
from vat_cat vc
group by vc.id
) _
Kind regards,
Stefan Houtzager
Houtzager ICT consultancy & development
www.linkedin.com/in/stefanhoutzager
Stefan Houtzager
Houtzager ICT consultancy & development
www.linkedin.com/in/stefanhoutzager
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