Azure stream analytics how to flatten json array - azure-stream-analytics

Question

I have a task where i need to flatten some json arrays
say my sample json is and i want to flatten the two arrays temperature_Readings and airpollution readings i.e my result must have 5 rows and the columns for air_pollution(array value) should be empty
How do I do this?
Sample JSON
{
"sensor_readings": {
"readings":{
"temperature_readings": [
{
"date": "02-02-2020",
"hour": "12",
"second": "00",
"temperature": "22.12C"
},
{
"date": "02-02-2020",
"hour": "13",
"second": "00",
"temperature": "22.2C"
},
{
"date": "02-02-2020",
"hour": "14",
"second": "00",
"temperature": "12.12C"
},
{
"date": "02-02-2020",
"hour": "15",
"second": "00",
"temperature": "22.12C"
},
{
"date": "02-02-2020",
"hour": "16",
"second": "00",
"temperature": "22.12C"
}
]
,
"air_pollution_readings":
[
{
"date": "02-02-2020",
"hour": "12",
"second": "00",
"element":"o3",
"particulate": "2.2"
},
{
"date": "02-02-2020",
"hour": "13",
"second": "00",
"element":"o3",
"particulate": "2.1"
}
]}
}
,
"siteid": "a1234566",
"deviceid": "2343434"
}
Thanks
Regards
Priya

Answer 1

Here is an idea of how you can 'unpack' your array of readings.
with sensorReadings as (Select sensor_readings.readings.temperature_readings from input),
inputValues as (Select message.ArrayValue as Data from sensorReadings CROSS APPLY GetArrayElements(sensorReadings.temperature_readings) as message)
SELECT *
INTO output
FROM inputValues