Re: [SQL] Better way to sort a JSONB array?
От | Michael Moore |
---|---|
Тема | Re: [SQL] Better way to sort a JSONB array? |
Дата | |
Msg-id | CACpWLjNyjBu_+F_eYO6aavyvz6iaH5qHqijCn3woKsFNPh0Q_Q@mail.gmail.com обсуждение исходный текст |
Ответ на | Re: [SQL] Better way to sort a JSONB array? (Michael Moore <michaeljmoore@gmail.com>) |
Список | pgsql-sql |
Almost forgot, here is the DDL on the json table structure.
CREATE TYPE ypxportal2__fgetquestions AS
(question_seq bigint,
prompt_seq bigint,
attribute_name character varying(150),
back_end_value character varying(1000),
display_text character varying(4000),
select_type character varying(30),
prompt_type_code character varying(50),
input_required character varying(1),
inacceptable_choice character varying(1),
answer_filter_flag character varying(1),
event_handler character varying(4000),
suppress_question_codename character varying(200),
all_questions_on_one_page_flag character varying(1),
attrib_values_of_question text,
qg_question_grp_key bigint,
qg_quest_set2tx_question_set bigint,
qg_lang2tx_question_language bigint,
qg_pvs2tx_portal_vendor_serv bigint,
qg_service2tx_service_catalog bigint,
qg_label character varying(100),
qg_form_name character varying(100),
qg_event_handler character varying(50),
qg_portal_ven2tx_portal_vendor bigint,
qg_portal2tx_portal bigint,
qg_vendor2tx_vendor bigint,
qg_dealer2tx_dealer bigint,
qg_edunamecode character varying(100),
qg_subjnamecode character varying(100),
qg_qualnamecode character varying(100),
question_prompt_type_code character varying(150),
question_key bigint,
score bigint,
qg_key2tx_criteria_tree bigint,
qg_state2tstateprovince character varying(2));
ALTER TYPE ypxportal2__fgetquestions
OWNER TO qsn_app;
On Mon, Aug 7, 2017 at 2:36 PM, Michael Moore <michaeljmoore@gmail.com> wrote:
As an aside, I had this entire pgsql function written using temp tables. Now our DBA has decided to run this in a read-only database, so temp tables are out. I'm trying to use jsonb in place of these temp tables. The output of this function is the entire result set in a specific sort order.Fun stuff! Back to the problem at hand, I think that ->> only allows one to address the nth element of the array. I don't see how I would get from there to sorting the entire jsonb array in portal_name order.If I know a ton about Postgres, then Postgres must weight about 2000 tons. Still very much to learn. :-)On Mon, Aug 7, 2017 at 2:17 PM, Steve Midgley <science@misuse.org> wrote:On Mon, Aug 7, 2017 at 2:12 PM, Michael Moore <michaeljmoore@gmail.com> wrote:json_table2 is declared as a variable in pgsql. It is not a jsonb table column. It is loaded from a statement like:
execute 'select jsonb_agg(row_to_json(zzz)) from (...extremely complex query goes here) zzz' into json_table2;Later, additional rows are added like:for a in select * from [table with the same columns as json_table_2]loopjson_table2 = coalesce (json_table2 || jsonb_agg(row_to_json (a)), jsonb_agg(row_to_json (a)) );end loop;So, because of the fact that the json_table2 is appended to in a random order, json_table2 now must be sorted.thanksOn Mon, Aug 7, 2017 at 1:51 PM, Steve Midgley <science@misuse.org> wrote:On Mon, Aug 7, 2017 at 1:13 PM, Michael Moore <michaeljmoore@gmail.com> wrote:This works, but surely there is a better way to do it:select jsonb_agg(row_to_json(alias)) from(Select * from jsonb_populate_recordset(null::tx_portal, json_table2) order by portal_name) alias into json_table2;It sorts the json_table2 array in "portal_name" order.I'm confused why you can't just pull portal_name from the json structure using "->"? For example, assuming your json structure that looks like:{"portal_name": "some data.."}And a table that looks like:| id | json_field |Wouldn't this sql work:select * from json_tableorder by json_field->'portal_name'Can you provide the final structure of json_table2 in DDL or similar?If "->" isn't right (b/c it's an array), would "->>[n]" work (if you know the array element you want to sort by - presumably "0")? That would sort by the first element in the array.I'm just confused about your question (and knowing you know a ton about Postgres), as to why, once you have a stable table structure in json_table2, why you can't just use standard sql and json operators to pinpoint the data you want and order on it..
В списке pgsql-sql по дате отправления: