查找问题！(40分)

H

hfutzhu

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• 2008-06-28

• #1

数据库里的一些字段如下：<br>&nbsp; &nbsp;Voltage_A &nbsp;Voltage_B Voltage_C Current_A &nbsp;Current_B Current_C &nbsp;ReTime<br><br>&nbsp; &nbsp;从前6个子段中统计出最大值和最小值，再把出现最大值和最小值得时间（ReTime）也取出来，用select max(Voltage_A) as max1,.....min(Voltage_A) as min1.......先取出最大值和最小值，然后再用select ReTime from db where Voltage_A = ...这样取得话感觉好麻烦，哪位兄弟有好点的思路哦？？？先谢谢了！

 

C

ch2001023

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• 2008-06-29

• #2

可以用1个临时表,来存储各个数据,然后再统一查询,,

 

A

Adao213

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• 2008-06-30

• #3

没看懂。<br>你的最大值和最小值是前六个字段各取，还是所有六个字段里的最大值、最小值

 

A

Adao213

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• 2008-06-30

• #4

select ReTime from db where Voltage_A = (select max(Voltage_A) from )<br>unioan all<br>select ReTime from db where Voltage_A = (select min(Voltage_A) from )<br>……

 

H

hfutzhu

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• 2008-07-01

• #5

是每个字段的最大值和最小值以及出现最大值最小值得时间，Retime

 

H

hfutzhu

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• 2008-07-01

• #6

要求每个字段的最大值，最小值以及出现的时间，