Another option is to use SQLites LAST_VALUE()
function in the following way.
Given this table:
+--------+---------+-------+
| OBJECT | STATUS | TIME |
+--------+---------+-------+
| | | |
| 1 | ON | 100 |
| | | |
| 1 | OFF | 102 |
| | | |
| 1 | ON | 103 |
| | | |
| 2 | ON | 101 |
| | | |
| 2 | OFF | 102 |
| | | |
| 2 | ON | 103 |
| | | |
| 3 | OFF | 102 |
| | | |
| 3 | ON | 103 |
+--------+---------+-------+
You can get the last status of every object with the following query
SELECT
DISTINCT OBJECT, -- Only unique rows
LAST_VALUE(STATUS) OVER ( -- The last value of the status column
PARTITION BY OBJECT -- Taking into account rows with the same value in the object column
ORDER by time asc -- "Last" when sorting the rows of every object by the time column in ascending order
RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING -- Take all rows in the patition
) as lastStatus
FROM
TABLE
The result would look like:
+--------+--------------+
| OBJECT | LAST_STATUS |
+--------+--------------+
| | |
| 1 | ON |
| | |
| 2 | ON |
| | |
| 3 | ON |
+--------+--------------+