Use the FILL clause to replace missing values with NULL for timebuckets with missing values.
The example shows the results of the query when the FILL clause is used with NULLS:
SELECT $TD_TIMECODE_RANGE, $TD_GROUP_BY_TIME, BUOYID, AVG(TEMPERATURE) FROM OCEAN_BUOYS WHERE TD_TIMECODE BETWEEN TIMESTAMP '2014-01-06 09:45:00' AND TIMESTAMP '2014-01-06 11:45:00' AND BUOYID=44 GROUP BY TIME (MINUTES(15) AND BUOYID) FILL(NULLS) ORDER BY 2,3;
Result: The timebuckets with no value are included in the result set, with nulls in place of the missing values.
TIMECODE_RANGE | GROUP BY TIME(MINUTES(15)) | BUOYID | AVG(TEMPERATURE) |
---|---|---|---|
('2014-01-06 09:45:00.000000+00:00', '2014-01-06 10:00:00.000000+00:00') | 1 | 44 | ? |
('2014-01-06 10:00:00.000000+00:00', '2014-01-06 10:15:00.000000+00:00') | 2 | 44 | 49 |
('2014-01-06 10:15:00.000000+00:00', '2014-01-06 10:30:00.000000+00:00') | 3 | 44 | ? |
('2014-01-06 10:30:00.000000+00:00', '2014-01-06 10:45:00.000000+00:00') | 4 | 44 | 43 |
('2014-01-06 10:45:00.000000+00:00', '2014-01-06 11:00:00.000000+00:00') | 5 | 44 | 43 |
('2014-01-06 11:00:00.000000+00:00', '2014-01-06 11:15:00.000000+00:00') | 6 | 44 | ? |
('2014-01-06 11:15:00.000000+00:00', '2014-01-06 11:30:00.000000+00:00') | 7 | 44 | ? |
('2014-01-06 11:30:00.000000+00:00', '2014-01-06 11:45:00.000000+00:00') | 8 | 44 | ? |