Finding the highest flow period for a day

Question

Now I really got stuck. I need to find what period for a day (full 24h) that have the highest flow. To make things a bit harder we cant used fixed periods. We have the flow per minute to work with.
Example with 10 minutes and we look for a 5 minute period:
Time ; Flow
0700 ; 14
0701 ; 12
0702 ; 18
0703 ; 19
0704 ; 12
0705 ; 16
0706 ; 10
0707 ; 10
0708 ; 15
0709 ; 14
In this case the highest flow for the period would be between 0701 and 0705 with a total flow of 77. So the needed answer would be 0701 and 77
In the situation where it will used in reality it will be finding a 15 minute period from 1440 minutes we have for a day.
I hope someone can provide me with ideas of how to solve this thing.
Regards,
Jonas

Answer 1

Are you guaranteed to have a row for every minute?
Oracle9i Enterprise Edition Release 9.2.0.6.0 - 64bit Production
JServer Release 9.2.0.6.0 - Production
SQL> DROP TABLE t;
Table dropped.
SQL> CREATE TABLE t (time VARCHAR2 (4), flow NUMBER);
Table created.
SQL> INSERT INTO t VALUES ('0700', 14);
1 row created.
SQL> INSERT INTO t VALUES ('0701', 12);
1 row created.
SQL> INSERT INTO t VALUES ('0702', 18);
1 row created.
SQL> INSERT INTO t VALUES ('0703', 19);
1 row created.
SQL> INSERT INTO t VALUES ('0704', 12);
1 row created.
SQL> INSERT INTO t VALUES ('0705', 16);
1 row created.
SQL> INSERT INTO t VALUES ('0706', 10);
1 row created.
SQL> INSERT INTO t VALUES ('0707', 10);
1 row created.
SQL> INSERT INTO t VALUES ('0708', 15);
1 row created.
SQL> INSERT INTO t VALUES ('0709', 14);
1 row created.
SQL> COMMIT;
Commit complete.
SQL> SELECT time, flow
  2  FROM  (SELECT time, flow,
  3                RANK () OVER (
  4         ORDER BY flow DESC) flow_rank
  5         FROM  (SELECT TO_CHAR (time, 'HH24MI') time,
  6                       SUM (flow) OVER (ORDER BY time
  7                         ROWS BETWEEN CURRENT ROW AND 4 FOLLOWING) flow
  8                FROM  (SELECT TO_DATE (time, 'HH24MI') time, flow
  9                       FROM   t)))
10  WHERE  flow_rank = 1;
TIME       FLOW
0701         77
SQL>