假设有如下场景:
电表,大家都知道电表读数并不是真正的耗电量,真正耗电量=此次读数-上一次读数
电表设计如下:
SQL语句如下,使用Oracle的FIRST_VALUE()和LAST_VALUE()函数实现:
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
结果:
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原文链接:https://blog.csdn.net/rongtaoup/article/details/82253615