Postgres 13

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create table rules (id int,   type  text, field text, operator text, criteria text);
insert into rules values 
(1, 'people', 'age', '>', '30'), 
(2, 'people', 'name', '==', '"Alice"');


create table people (id int, name text, age int);
insert into people
values
  (1, 'Emma', 34),
  (2, 'Larry', 25),
  (3, 'Alice', 22),
  (4, 'Thomas', 31)
;

CREATE TABLE



INSERT 0 2



CREATE TABLE



INSERT 0 4


with cte_rule as (
  select (concat('$.', field, ' ', operator, ' ', criteria))::jsonpath as rule
  from rules
  where id = 1
)
select p.*
from people p
where to_jsonb(p) @@ (select rule from cte_rule)


id
name
age


1
Emma
34

4
Thomas
31



SELECT 2


with cte_rule as (
  select (concat('$.', field, ' ', operator, ' ', criteria))::jsonpath as rule
  from rules
  where id = 2
)
select p.*
from people p
where to_jsonb(p) @@ (select rule from cte_rule)


id
name
age


3
Alice
22



SELECT 1