请教:取得表中上下两条数据的差值,有什么好办法吗?请赐教!
Hasen 2005-09-28 12:33:24
有如下的表Table1
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receiveTime KwPower
2005-07-01 00:03:32 140.50
2005-07-02 00:01:01 200.00
2005-07-03 00:11:30 294.00
2005-07-04 00:01:00 381.50
2005-07-05 00:02:10 438.50
2005-07-06 00:09:04 622.00
请教:如果想得到如下的查询结果,怎么写SQL语句呀?
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thisMonth KwPower (KwPower即一个月中每天0点功率的差)
01 59.50
02 94.00
03 87.50
04 57.00
... .....
... .....