Postgres 15

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create table market (fruit varchar(10), price int);

CREATE TABLE

insert into market (fruit, price) values ('apple', 2), ('banana', 3), ('grape', 1);

INSERT 0 3

select * from market;

fruit
price

apple
2

banana
3

grape
1

SELECT 3

with recursive
n as (
  select cast(fruit as character varying), price from market
 union all
  select concat(m.fruit, '+', n.fruit), m.price + n.price
  from n
  join market m on m.fruit > n.fruit
)
select * from n;

fruit
price

apple
2

banana
3

grape
1

banana+apple
5

grape+apple
3

grape+banana
4

grape+banana+apple
6

SELECT 7

fruit	price
apple	2
banana	3
grape	1
banana+apple	5
grape+apple	3
grape+banana	4
grape+banana+apple	6