Oracle gets the last and first data (gets the first and last data by time)

Let 's say we have the following scenario ：

Electric meter , Everyone knows that the reading of electricity meter is not the real power consumption , Real power consumption = This reading - Last reading

The meter design is as follows ：

SQL The statement is as follows , Use Oracle Of FIRST_VALUE() and LAST_VALUE() Function implementation ：

SELECT 
	DISTINCT
	LAST_VALUE (E_VALUE) OVER (PARTITION BY E_CODE ORDER BY E_DATE ROWS BETWEEN unbounded preceding AND unbounded following) AS LAST_TIME_VALUE,
	FIRST_VALUE (E_VALUE) OVER (PARTITION BY E_CODE ORDER BY E_DATE ROWS BETWEEN unbounded preceding AND unbounded following) AS FIRST_TIME_VALUE
FROM 
	TABLE_TEST

result ：