我有DeviceMaster和DeviceStatus的表。 其中DeviceMaster是设备的主设备,而DeviceStatus是设备的状态。现在我想要使用DeviceMasterId获取每个设备的最新DeviceStatus记录,并且根据最后一个记录(降序)。创建SQL查询
例如。
DeviceName RecordCreatedDate Status
ElectronicRod 14/11/2011 12:00:00 On
ElectronicRod 14/11/2011 11:30:00 Off
尽管在DeviceStatus中有多个记录。
这里是表结构
DeviceMaster
[Id] [int],
[ROId] [int] ,
[ClientId] [int] ,
[DeviceTypeId] [int] ,
[Label] [varchar](50) ,
[ClientCommChannelId] [int] ,
[ServerCommChannelId] [bigint] ,
[DeviceName] [varchar](50) ,
[Address] [varchar](50) ,
[Attribute1] [varchar](50) ,
[Attribute2] [varchar](50) ,
[Attribute3] [varchar](50) ,
[IsDeleted] [bit] ,
[RecordCreatedDate] [datetime] ,
[RecordUpdatedDate] [datetime] ,
[RecordCreatedBy] [int] ,
[RecordUpdatedBy] [int] ,
[IsTransfered] [bit]
DeviceStatus
[Id] [bigint],
[ROId] [int],
[ClientId] [int],
[ServerDeviceId] [bigint] , --It is the foreign key reference of Device Id
[ClientDeviceId] [int] ,
[Status] [bit] ,
[TimeStamp] [datetime] ,
[Attribute1] [varchar](50) ,
[Attribute2] [varchar](50) ,
[Attribute3] [varchar](50) ,
[RecordCreatedDate] [datetime] ,
[RecordUpdatedDate] [datetime] ,
[RecordCreatedBy] [int] ,
[RecordUpdatedBy] [int] ,
[IsTransfered] [bit]
DeviceStatus具有多行条目单device.I需要最新DeviceStatus每个和每个设备。
预先感谢您
你可以发表表格结构吗?你还有什么尝试过自己?你有任何代码等? – Purplegoldfish
@Purplegoldfish sure –
您能否澄清DeviceStatus是否是一个审计表,显示状态更改的历史记录,而不是当前状态。 –