Postgres 11

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create table contracts (
    id serial primary key,
    personID int,
    data jsonb
);

insert into contracts (personID, data) values
( 1, '{ "dates": [28.3, 27.0] }'::jsonb),
( 2, '{ "dates": [38.2, 27.0] }'::jsonb),
( 3, '{ "dates": [23.2, 25.0, 34.0, 36.4] }'::jsonb);

CREATE INDEX di ON contracts using GIN(data);
3 rows affected

SELECT c.id, c.personID, s2.*
FROM contracts c
,LATERAL (SELECT (data) ) s(c)
,LATERAL ( VALUES(
          (SELECT MIN(value::text::decimal(10,2))
          FROM json_array_elements((s.c -> 'dates')::json) x),
          (SELECT MAX(value::text::decimal(10,2))
          FROM json_array_elements((s.c -> 'dates')::json) x))
         )s2("start","end")
WHERE s2.end > 35;


id
personid
start
end


2
2
27.00
38.20

3
3
23.20
36.40


select version();


version


PostgreSQL 11.9 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 8.3.1 20191121 (Red Hat 8.3.1-5), 64-bit