Question

我有一个包含此架构的表：

DeviceID int
RoomID int
DateInstalled datetime

表格数据的样本如下：

DeviceID   RoomID   DateInstalled
0001       Room1    1/1/2000  
0002       Room1    1/1/2000  
0001       Room2    2/1/2000

我需要构建一个查询，它会告诉我每个设备在特定房间的日期范围。类似的东西：

DeviceID   RoomID   From Date    To Date
0001       Room1    1/1/2000     1/31/2000 
0001       Room2    2/1/2000     NULL 
0002       Room1    1/1/2000     NULL

Answer 1

试一试：

select a.DeviceID, a.RoomID, a.DateInstalled as fromDate, 
    ISNULL((select DATEADD(day,-1,MIN(DateInstalled)) from myTable
            where DeviceID = a.DeviceID
            and RoomID <> a.RoomID
            and DateInstalled > a.DateInstalled),'') as toDate
from myTable a

如何从记录中计算日期范围

1 个答案: