Oracle 18c

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CREATE TABLE view_count_sum (date_rw, buysum, totalsum) AS
SELECT 10,  1,  1 FROM DUAL UNION ALL
SELECT  9,  2,  2 FROM DUAL UNION ALL
SELECT  8,  3,  3 FROM DUAL UNION ALL
SELECT  7,  4,  4 FROM DUAL UNION ALL
SELECT  6,  5,  5 FROM DUAL UNION ALL
SELECT  5,  6,  6 FROM DUAL UNION ALL
SELECT  4,  7,  7 FROM DUAL UNION ALL
SELECT  3,  8,  8 FROM DUAL UNION ALL
SELECT  2,  9,  9 FROM DUAL UNION ALL
SELECT  1, 10, 10 FROM DUAL;
10 rows affected

SELECT json_object(
         'buy'   VALUE JSON_ARRAYAGG(b.buysum),
         'total' VALUE JSON_ARRAYAGG(b.totalsum)
       ) AS json
FROM   (
  select *
  from   view_count_sum
  ORDER BY date_rw DESC
  FETCH FIRST 10 ROWS ONLY
) b
ORDER BY b.date_rw;


JSON


{"buy":[1,2,3,4,5,6,7,8,9,10],"total":[1,10,9,8,7,6,5,4,3,2]}


SELECT json_object(
         'buy'   VALUE JSON_ARRAYAGG(b.buysum   ORDER BY b.date_RW DESC),
         'total' VALUE JSON_ARRAYAGG(b.totalsum ORDER BY b.date_RW DESC)
       ) AS json
FROM   (
  select *
  from   view_count_sum
  ORDER BY date_rw DESC
  FETCH FIRST 10 ROWS ONLY
) b;


JSON


{"buy":[1,2,3,4,5,6,7,8,9,10],"total":[1,2,3,4,5,6,7,8,9,10]}