Question

我有一个包含带时间戳数据的表。数据值是在不同的参考系中测量的，因此在下面的例子中，A由B测量，但是B由C测量。我可以通过查找A的值来估计如果用C测量的A将是什么。＆gt; B和B-> C用于相同的时间戳，并将它们加在一起。我一直在尝试编写一个查询，该查询采用每个A-> B测量，查找最接近的B-> C测量，并返回TimestampA，ValueA，TimestampB，ValueB，Value A + B.有人可以帮忙吗？

TimeStamp       ID  ParentID    Value  
19:44:04.877    A   B           176.5429  
19:44:04.877    A   B           176.2653  
19:44:09.893    A   B           170.5266  
19:44:09.893    A   B           170.883  
19:44:14.887    A   B           164.3122  
19:44:14.887    A   B           164.1429  
19:44:19.880    A   B           158.5632  
19:44:19.880    A   B           158.1787  
19:44:24.870    A   B           153.0709  
19:44:24.870    A   B           152.8471  
19:44:00.403    B   C           195184.2  
19:44:05.443    B   C           195189.8  
19:44:10.450    B   C           195195.4  
19:44:15.487    B   C           195201.3  
19:44:20.523    B   C           195207.2  
19:44:25.570    B   C           195212.6

Answer 1

你可以自己LEFT JOIN表，看看：

SELECT  this.TimeStamp AS [this TimeStamp], 
        this.Value AS [this Value], 
        parent.Timestamp AS [parent Timestamp], 
        parent.Value AS [parent Value], 
        this.Value + ISNULL(parent.Value, 0) AS [Total Value]
FROM dbo.TableName this
LEFT OUTER JOIN dbo.TableName parent
  ON  this.ParentID = parent.ID
  AND parent.Value = (SELECT MIN(Value)FROM dbo.TableName p
                      WHERE p.ID = this.ParentID
                      AND p.Value >= this.Value)

Here's a demo

TSQL：根据时间在单个表中组合记录

1 个答案: