Oracle 21c

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CREATE TABLE TURNOVER_TABLE (
    SUPPLIER_PROD VARCHAR(255),
    SUPPLIER_AUS VARCHAR(255),
    TURNOVER INT
);
INSERT INTO TURNOVER_TABLE (SUPPLIER_PROD, SUPPLIER_AUS, TURNOVER)
VALUES ('Bosch', 'Bosch', 10);
1 rows affected

INSERT INTO TURNOVER_TABLE (SUPPLIER_PROD, SUPPLIER_AUS, TURNOVER)
VALUES ('Bosch', 'Magna', 1);
1 rows affected

INSERT INTO TURNOVER_TABLE (SUPPLIER_PROD, SUPPLIER_AUS, TURNOVER)
VALUES ('Magna', 'Bosch', 1);
1 rows affected

select supplier_prod, turnover
from turnover_table
union all
select supplier_aus, turnover
from turnover_table
where supplier_aus != supplier_prod;


SUPPLIER_PROD
TURNOVER


Bosch
10

Bosch
1

Magna
1

Magna
1

Bosch
1


select supplier_prod, sum(turnover) as turnover
from (
  select supplier_prod, turnover
  from turnover_table
  union all
  select supplier_aus, turnover
  from turnover_table
  where supplier_aus != supplier_prod
)
group by supplier_prod;


SUPPLIER_PROD
TURNOVER


Bosch
12

Magna
2