How to use JSON array in JOIN? - postgresql

Question

I have got follow data base schema:
CREATE TABLE "public"."regions" (
"id" Integer DEFAULT nextval('regions_id_seq'::regclass) NOT NULL,
"ru_name" Character Varying( 100 ),
"translite_name" Character Varying( 100 ),
PRIMARY KEY ( "id" ) );
;
CREATE TABLE "public"."tokens" (
"user_id" BigInt NOT NULL,
"token_start_date" Timestamp Without Time Zone NOT NULL,
"token_end_date" Timestamp Without Time Zone NOT NULL,
"regions" JSON,
"id" Character( 1 ) NOT NULL,
"access_token" Character Varying( 50 ) NOT NULL,
PRIMARY KEY ( "id" ) );
;
CREATE TABLE "public"."users" (
"id" BigInt DEFAULT nextval('user_id_sequence'::regclass) NOT NULL,
"registration_date" Timestamp Without Time Zone NOT NULL,
"name" Character Varying( 50 ) NOT NULL,
"lastname" Character Varying NOT NULL,
"email" Character Varying NOT NULL,
PRIMARY KEY ( "id" ),
CONSTRAINT "unique_users_email" UNIQUE( "email" ) );
;
I need to display for every user date of expiring token and regions names for this token.
Something like:
user_id token_end_date region_as_json_object
5 "2021-12-27" [{id: 1, ru_name:"Region1"}, {id: 2, ru_name:"Region2"}]
I wrote next code:
SELECT
ru_name
FROM "tokens"
JOIN regions ON regions.id = ANY (json_array_elements_text(regions) )
WHERE user_id = 5 ;
But it does not work.
sample data:
--
-- PostgreSQL database dump
--
-- Dumped from database version 13.1
-- Dumped by pg_dump version 13.1
SET statement_timeout = 0;
SET lock_timeout = 0;
SET idle_in_transaction_session_timeout = 0;
SET client_encoding = 'UTF8';
SET standard_conforming_strings = on;
SELECT pg_catalog.set_config('search_path', '', false);
SET check_function_bodies = false;
SET xmloption = content;
SET client_min_messages = warning;
SET row_security = off;
SET default_tablespace = '';
SET default_table_access_method = heap;
--
-- Name: regions; Type: TABLE; Schema: public; Owner: postgres
--
CREATE TABLE public.regions (
id integer NOT NULL,
ru_name character varying(100),
fz223_name character varying(100),
fz44_name character varying(100),
translite_name character varying(100)
);
ALTER TABLE public.regions OWNER TO postgres;
--
-- Name: regions_id_seq; Type: SEQUENCE; Schema: public; Owner: postgres
--
CREATE SEQUENCE public.regions_id_seq
AS integer
START WITH 1
INCREMENT BY 1
NO MINVALUE
NO MAXVALUE
CACHE 1;
ALTER TABLE public.regions_id_seq OWNER TO postgres;
--
-- Name: regions_id_seq; Type: SEQUENCE OWNED BY; Schema: public; Owner: postgres
--
ALTER SEQUENCE public.regions_id_seq OWNED BY public.regions.id;
--
-- Name: tokens; Type: TABLE; Schema: public; Owner: postgres
--
CREATE TABLE public.tokens (
id character(1) NOT NULL,
user_id bigint NOT NULL,
token_start_date timestamp without time zone NOT NULL,
token_end_date timestamp without time zone NOT NULL,
access_token character varying(50) NOT NULL,
regions json
);
ALTER TABLE public.tokens OWNER TO postgres;
--
-- Name: users; Type: TABLE; Schema: public; Owner: postgres
--
CREATE TABLE public.users (
id bigint DEFAULT nextval('public.user_id_sequence'::regclass) NOT NULL,
name character varying(50) NOT NULL,
lastname character varying NOT NULL,
email character varying NOT NULL,
registration_date timestamp without time zone NOT NULL
);
ALTER TABLE public.users OWNER TO postgres;
--
-- Name: regions id; Type: DEFAULT; Schema: public; Owner: postgres
--
ALTER TABLE ONLY public.regions ALTER COLUMN id SET DEFAULT nextval('public.regions_id_seq'::regclass);
--
-- Data for Name: regions; Type: TABLE DATA; Schema: public; Owner: postgres
--
INSERT INTO public.regions VALUES
(1, 'Адыгейская республика', 'Adygeya_Resp', 'Adygeja_Resp', 'Adygejskaya_respublika'),
(2, 'Алтайский край', 'Altayskii__krai', 'Altajskij_kraj', 'Altajskij_kraj'),
(3, 'Алтайская республика', 'Altay_Resp', 'Altaj_Resp', 'Altajskaya_respublika'),
(4, 'Амурская область', 'Amurskaya_obl', 'Amurskaja_obl', 'Amurskaya_oblast'),
(5, 'Архангельская область', 'Arhangelskaya_obl', 'Arkhangelskaja_obl', 'Arhangelskaya_oblast'),
(6, 'Астраханская область', 'Astrahanskaya_obl', 'Astrakhanskaja_obl', 'Astrahanskaya_oblast'),
(7, 'Байконур', 'Baikonur_g', 'Bajkonur_g', 'Bajkonur'),
(8, 'Башкортостан', 'Bashkortostan_Resp', 'Bashkortostan_Resp', 'Bashkortostan'),
(9, 'Белгородская область', 'Belgorodskaya_obl', 'Belgorodskaja_obl', 'Belgorodskaya_oblast'),
(10, 'Брянская область', 'Brianskaya_obl', 'Brjanskaja_obl', 'Bryanskaya_oblast'),
(11, 'Бурятская область', 'Buryatiya_Resp', 'Burjatija_Resp', 'Buryatskaya_oblast');
--
-- Data for Name: tokens; Type: TABLE DATA; Schema: public; Owner: postgres
--
INSERT INTO public.tokens VALUES
('1', 3, '2020-03-05 00:00:00', '2020-03-08 00:00:00', 'sdfa78saaf4', NULL),
('2', 3, '2020-04-08 00:00:00', '2020-04-18 00:00:00', 'asasdfgkfaf4', NULL),
('3', 3, '2020-05-15 00:00:00', '2020-09-25 00:00:00', '934rfeasfsad', '[1,2,4]'),
('4', 3, '2020-05-15 00:00:00', '2020-09-25 00:00:00', '934rfeasfsad', '[4,5,7]'),
('5', 5, '2021-05-15 00:00:00', '2021-12-25 00:00:00', '934rfeasfsad', '[1,4,6,8]'),
('6', 5, '2021-06-15 00:00:00', '2022-01-25 00:00:00', '934rfeasfsad', '[12]');
--
-- Data for Name: users; Type: TABLE DATA; Schema: public; Owner: postgres
--
INSERT INTO public.users VALUES
(3, 'Mike', 'Klinton', 'mike#gmail.com', '2010-01-02 00:00:00'),
(5, 'Piter', 'Miklson', 'piter#gmail.com', '2011-01-02 00:00:00');
--
-- Name: regions_id_seq; Type: SEQUENCE SET; Schema: public; Owner: postgres
--
SELECT pg_catalog.setval('public.regions_id_seq', 1, false);
--
-- Name: regions regions_pkey; Type: CONSTRAINT; Schema: public; Owner: postgres
--
ALTER TABLE ONLY public.regions
ADD CONSTRAINT regions_pkey PRIMARY KEY (id);
--
-- Name: tokens tokens_pkey; Type: CONSTRAINT; Schema: public; Owner: postgres
--
ALTER TABLE ONLY public.tokens
ADD CONSTRAINT tokens_pkey PRIMARY KEY (id);
--
-- Name: users unique_users_email; Type: CONSTRAINT; Schema: public; Owner: postgres
--
ALTER TABLE ONLY public.users
ADD CONSTRAINT unique_users_email UNIQUE (email);
--
-- Name: users users_pkey; Type: CONSTRAINT; Schema: public; Owner: postgres
--
ALTER TABLE ONLY public.users
ADD CONSTRAINT users_pkey PRIMARY KEY (id);
--
-- Name: tokens userr_id_fk; Type: FK CONSTRAINT; Schema: public; Owner: postgres
--
ALTER TABLE ONLY public.tokens
ADD CONSTRAINT userr_id_fk FOREIGN KEY (user_id) REFERENCES public.users(id) MATCH FULL ON UPDATE CASCADE ON DELETE CASCADE;
--
-- PostgreSQL database dump complete
--

Answer 1

select user_id, token_end_date::date,
json_agg(json_build_object('id',region_id,'ru_name',ru_name)) as regions_json_object
from
(
select user_id, token_end_date,
json_array_elements_text(regions)::integer as region_id
from tokens
) as t
join regions on t.region_id = regions.id
group by user_id, token_end_date;

Answer 2

Try this :
SELECT
ru_name
FROM
( SELECT json_array_elements_text(regions) AS r
FROM public.tokens
WHERE user_id = 5
) AS r
JOIN public.regions
ON regions.id = r :: integer ;
see the result in dbfiddle

Answer 3

You can use CROSS JOIN and after collecting, data use JOIN for combine data.
Demo
with data as (
select
t.*,
(ej.value ->> 'id')::int as region_id
from
"public"."tokens" t
cross join json_array_elements(t.regions) ej
where
user_id = 5
)
select
r.ru_name
from
"public"."regions" r
inner join data d on d.region_id = r.id