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我有一个传感器，它以以下格式（通过 Modbus 服务器）向 IoTHub 报告数据：

15/05/2018 14:56:56> Device: [dev], Data:[[{"DisplayName":"Temperature","HwId":"PI-1","Address":"400002","Value":"192","SourceTimestamp":"2018-05-15 13:56:52"},{"DisplayName":"Humidity","HwId":"PI-1","Address":"400001","Value":"397","SourceTimestamp":"2018-05-15 13:56:52"}]]Properties:
'content-type': 'application/edge-modbus-json'

15/05/2018 14:57:00> Device: [dev], Data:[[{"DisplayName":"Temperature","HwId":"PI-1","Address":"400002","Value":"201","SourceTimestamp":"2018-05-15 13:56:57"},{"DisplayName":"Humidity","HwId":"PI-1","Address":"400001","Value":"397","SourceTimestamp":"2018-05-15 13:56:57"}]]Properties:
'content-type': 'application/edge-modbus-json'

15/05/2018 14:57:06> Device: [dev], Data:[[{"DisplayName":"Temperature","HwId":"PI-1","Address":"400002","Value":"201","SourceTimestamp":"2018-05-15 13:57:02"},{"DisplayName":"Humidity","HwId":"PI-1","Address":"400001","Value":"397","SourceTimestamp":"2018-05-15 13:57:02"}]]Properties:
'content-type': 'application/edge-modbus-json'

15/05/2018 14:57:10> Device: [dev], Data:[[{"DisplayName":"Temperature","HwId":"PI-1","Address":"400002","Value":"195","SourceTimestamp":"2018-05-15 13:57:07"},{"DisplayName":"Humidity","HwId":"PI-1","Address":"400001","Value":"397","SourceTimestamp":"2018-05-15 13:57:07"}]]Properties:
'content-type': 'application/edge-modbus-json'

每个传感器都在一个单独的数组条目中报告，并在传感器的显示名称和值之间进行拆分。

我想要的是一个 JSON Payload，我可以将它输入 PowerBI，所以这需要按顺序排列：

时间戳：时间，湿度：湿度值，温度：温度值

如何构建合适的流分析查询来执行此操作？这种输入格式是典型的 Modbus 或 OPC-UA 类型设备，因此可能会遇到几次。

我尝试使用 GetArrayElement/(s) 但该数组在 JSON 中没有名称，因此没有可引用的内容。

4

2 回答 2

0

实际上找到了一种更简单的方法来直接处理这个没有函数。将 CASE 语句与 LAST 结合使用。

SELECT System.Timestamp as timestamp,

    CASE Address
        WHEN '400001' THEN cast(Value as float)/10 ELSE last(cast(Value as float)/10) over (partition by HwId limit duration(day,1) when Value is not null and Address like '400001')
    END
    AS Humidity,
    CASE Address
        WHEN '400002' THEN cast(Value as float)/10 ELSE last(cast(Value as float)/10) over (partition by HwId limit duration(day,1) when Value is not null and Address like '400002')
    END
    AS Temperature,
    CASE Address
        WHEN '400003' THEN cast(Value as float)/10 ELSE last(cast(Value as float)/10) over (partition by HwId limit duration(day,1) when Value is not null and Address like '400003')
    END
    AS Pressure    
INTO PowerBI
FROM IoTHub as event
于 2018-05-17T09:28:07.007 回答
0

据我了解，您可以利用Azure 流分析 JavaScript 用户定义函数来扁平化您的数据。

假设您的数据如下所示：

{
    Device:"dev01", 
    Data:[
    [
      {"DisplayName":"Temperature","HwId":"PI-1","Address":"400002","Value":"192","SourceTimestamp":"2018-05-15 13:56:52"}
      ,{"DisplayName":"Humidity","HwId":"PI-1","Address":"400001","Value":"397","SourceTimestamp":"2018-05-15 13:56:52"}
     ]
    ]
}

您可以创建以下 UDF：

GetValueByPropertyName：

function main(arrs,propertyname) {
    for(var i=0;i<arrs.length;i++){
       var item=arrs[i];
       if(item.hasOwnProperty(propertyname)){
           return item[propertyname];
       }
    }
    return '';
}

通过显示名称获取值：

function main(dataArr,displayname) {
    if(dataArr){
      for(var j=0;j<dataArr.length;j++)
      {
        var subArr=dataArr[j];
        for(var i=0;i<subArr.length;i++){
          var obj=subArr[i];
          if(obj.DisplayName.toLowerCase()==displayname.toLowerCase())
              return obj.Value;
        }
      }
    }
    return '';
}

示例查询：

select 
input.device as DeviceName,
UDF.GetValueByDisplayName(input.Data,'Temperature') as Temperature,
UDF.GetValueByDisplayName(input.Data,'Humidity') as Humidity,
UDF.GetValueByPropertyName(GetArrayElement(input.Data,0),'SourceTimestamp') as [Timestamp]
from input

测试：

在此处输入图像描述

于 2018-05-16T08:05:04.117 回答