Question

下面提到的代码可以更加紧凑，我试图将相同机架的电缆长度设置为相同的机架固定，其中长度固定为6mts，然后从一个机架到另一个机架，每个机架增加0.5mt并且剩下的是一些随机长度数据库r包含以下列

ID        RACK_A           RACK_B          LENGTH
1          RK 1             RK 1
2          RK 2             RK 1
3          RK 1             RK 2
4          MCR DESK         PCR
5          CAR              INGEST
6          PCR              CAR

等约2000个条目

UPDATE MASTER_SCHEDULE
SET CABLE_LENTH = 
    switch(
          RACK_A='RK 1' AND RACK_B='RK 1', 6
        , RACK_A='RK 2' AND RACK_B='RK 2', 6
        , RACK_A='RK 3' AND RACK_B='RK 3', 6
        , RACK_A='RK 4' AND RACK_B='RK 4', 6
        , RACK_A='RK 5' AND RACK_B='RK 5', 6
        , RACK_A='RK 6' AND RACK_B='RK 6', 6
        , RACK_A='RK 7' AND RACK_B='RK 7', 6
and so on say more 20 statements all with LENGTH = 6

        , RACK_A='RK 1' AND RACK_B='RK 2' OR RACK_A = 'RK 2' AND RACK_B = 'RK 1',6.5
        , RACK_A='RK 1' AND RACK_B='RK 3' OR RACK_A = 'RK 3' AND RACK_B = 'RK 1',7
        , RACK_A='RK 1' AND RACK_B='RK 4' OR RACK_A = 'RK 4' AND RACK_B = 'RK 1',7.5
        , RACK_A='RK 1' AND RACK_B='RK 5' OR RACK_A = 'RK 5' AND RACK_B = 'RK 1',8
        , RACK_A='RK 1' AND RACK_B='RK 6' OR RACK_A = 'RK 6' AND RACK_B = 'RK 1',8.5
        , RACK_A='RK 1' AND RACK_B='RK 7' OR RACK_A = 'RK 7' AND RACK_B = 'RK 1',9
and so on each LENGTH incremented by +.5

      ,  RACK_A= 'MCR DESK' AND RACK_B='PCR=' OR RACK_A= 'PCR' AND RACK_B='MCR_DESK',54
      ,  RACK_A= 'CAR' AND RACK_B='INGEST' OR RACK_A= 'INGEST' AND RACK_B='CAR',47 
  and so on each length is random figure ,        
        , true, 0)
WHERE ID>=1 AND ID<= 2000

Answer 1

下面是SQL Server的代码，我将在短时间内为您提供MS ACCESS的代码。但是如果您知道我在查询中使用的MS-ACCESS的类似功能，那么您可以自己尝试转换

UPDATE MASTER_SCHEDULE
SET LENGTH = ABS( CAST(SUBSTRING(RACK_A, CHARINDEX(' ',RACK_A)+1, LEN(RACK_A) - CHARINDEX   (' ',RACK_A)) AS INT)
-  CAST(SUBSTRING(RACK_B, CHARINDEX(' ',RACK_B)+1, LEN(RACK_B) - CHARINDEX(' ',RACK_B)) AS INT))  * 0.5 + 6

我在查询中执行的操作是提取列RACK_A和RACK_B的整数部分，减去值，取结果的绝对值（如果减法导致负值则需要），乘以0.5，最后加6。

看到它在SQL Fiddle工作：http://sqlfiddle.com/#!3/0abad/1

以下是MS-ACCESS的相应代码：

UPDATE MASTER_SCHEDULE SET MASTER_SCHEDULE.LENGTH = Abs(CInt(Mid(RACK_A,InStr(1,RACK_A,' ')+1,Len(RACK_A)-InStr(1,RACK_A,' ')))-CInt(Mid(RACK_B,InStr(1,RACK_B,' ')+1,Len(RACK_B)-InStr(1,RACK_B,' '))))*0.5+6;

让我知道它是否按预期工作。

Answer 2

根据此处给出的样本数据，我假设列RACK_A和RACK_B中的所有数据都具有格式“RK {Room Number}”。然后你可以尝试这个查询：

UPDATE MASTER_SCHEDULE
SET CABLE_LENTH = 
    ABS((RIGHT(RACK_A, LEN(RACK_A)-3) - RIGHT(RACK_B, LEN(RACK_B)-3)))
        *
    0.5
        +
    6
WHERE ID>=1 AND ID<= 2000

供参考：MS Access: Functions

如何计算两列条目的长度

2 个答案: