ORDER_DATE  ORDER_ID  PROD_ID  QTY    PRICE
01-JUL-16	1	P1	5	5
01-JUL-16	2	P2	2	10
01-JUL-16	3	P3	10	25
01-JUL-16	4	P1	20	5
02-JUL-16	5	P3	5	25
02-JUL-16	6	P4	6	20
02-JUL-16	7	P1	2	5
02-JUL-16	8	P5	1	50
02-JUL-16	9	P6	2	50
02-JUL-16	10	P2	4	10

SELECT MAX(SOLD_AMT) AS AMT FROM
(SELECT T1.*, QUANTITY * PRICE AS SOLD_AMT FROM T1)
GROUP BY ORDER_DATE

ORDER_DATE     PRODUCT_ID      AMT
01-JUL-11       P3             250
02-JUL-11       P3             125

SELECT TO_CHAR(TO_DATE('01-JUL-2016','DD-MON-YYYY'), 'DD-MON-YY') AS ORDER_DATE, 1 AS ORDER_ID, 'P1' AS PRODUCT_ID, 5 AS QUANTITY, 5 AS PRICE FROM DUAL
UNION ALL
SELECT TO_CHAR(TO_DATE('01-JUL-2016','DD-MON-YYYY'), 'DD-MON-YY'),  2, 'P2', 2, 10 FROM DUAL
UNION ALL
SELECT TO_CHAR(TO_DATE('01-JUL-2016','DD-MON-YYYY'), 'DD-MON-YY'), 3, 'P3', 10, 25 FROM DUAL
UNION ALL
SELECT TO_CHAR(TO_DATE('01-JUL-2016','DD-MON-YYYY'), 'DD-MON-YY'), 4, 'P1', 20, 5 FROM DUAL
UNION ALL
SELECT TO_CHAR(TO_DATE('02-JUL-2016','DD-MON-YYYY'), 'DD-MON-YY'), 5, 'P3', 5, 25 FROM DUAL
UNION ALL
SELECT TO_CHAR(TO_DATE('02-JUL-2016','DD-MON-YYYY'), 'DD-MON-YY'), 6, 'P4', 6,	20 FROM DUAL
UNION ALL
SELECT TO_CHAR(TO_DATE('02-JUL-2016','DD-MON-YYYY'), 'DD-MON-YY'), 7, 'P1', 2, 5 FROM DUAL
UNION ALL
SELECT TO_CHAR(TO_DATE('02-JUL-2016','DD-MON-YYYY'), 'DD-MON-YY'), 8, 'P5', 1, 50 FROM DUAL
UNION ALL
SELECT TO_CHAR(TO_DATE('02-JUL-2016','DD-MON-YYYY'), 'DD-MON-YY'), 9, 'P6', 2, 50 FROM DUAL
UNION ALL
SELECT TO_CHAR(TO_DATE('02-JUL-2016','DD-MON-YYYY'), 'DD-MON-YY'), 10, 'P2', 4, 10 FROM DUAL;

DATE      PRODUCT_ID   SOLD_AMOUNT
01-JUL-11    P3        250
02-JUL-11    P3        125

SQL> with t1 as (
  2  SELECT TO_DATE('01-JUL-2016','DD-MON-YYYY') AS ORDER_DATE, 1 AS ORDER_ID,
  3         'P1' AS PRODUCT_ID, 5 AS QUANTITY, 5 AS PRICE
  4  FROM DUAL
  5  UNION ALL
  6  SELECT TO_DATE('01-JUL-2016','DD-MON-YYYY'),  2, 'P2', 2, 10 FROM DUAL
  7  UNION ALL
  8  SELECT TO_DATE('01-JUL-2016','DD-MON-YYYY'), 3, 'P3', 10, 25 FROM DUAL
  9  UNION ALL
 10  SELECT TO_DATE('01-JUL-2016','DD-MON-YYYY'), 4, 'P1', 20, 5 FROM DUAL
 11  UNION ALL
 12  SELECT TO_DATE('02-JUL-2016','DD-MON-YYYY'), 5, 'P3', 5, 25 FROM DUAL
 13  UNION ALL
 14  SELECT TO_DATE('02-JUL-2016','DD-MON-YYYY'), 6, 'P4', 6, 20 FROM DUAL
 15  UNION ALL
 16  SELECT TO_DATE('02-JUL-2016','DD-MON-YYYY'), 7, 'P1', 2, 5 FROM DUAL
 17  UNION ALL
 18  SELECT TO_DATE('02-JUL-2016','DD-MON-YYYY'), 8, 'P5', 1, 50 FROM DUAL
 19  UNION ALL
 20  SELECT TO_DATE('02-JUL-2016','DD-MON-YYYY'), 9, 'P6', 2, 50 FROM DUAL
 21  UNION ALL
 22  SELECT TO_DATE('02-JUL-2016','DD-MON-YYYY'), 10, 'P2', 4, 10 FROM DUAL
 23  ),
 24  data as (
 25    select ORDER_DATE, ORDER_ID, PRODUCT_ID, QUANTITY*PRICE amount,
 26           rank() over
 27             (partition by trunc(ORDER_DATE) order by QUANTITY*PRICE desc) rk
 28    from t1
 29  )
 30  select ORDER_DATE, ORDER_ID, PRODUCT_ID, amount
 31  from data
 32  where rk = 1
 33  /
ORDER_DATE    ORDER_ID PR     AMOUNT
----------- ---------- -- ----------
01-JUL-2016          3 P3        250
02-JUL-2016          5 P3        125