Answer by Manimaran Samuthirapandi for azure stream analytics to cosmos db

Try with

SELECT 
    concat(deviceId, cloudtagId) as telemetryid, value as temperature, id, deviceId, 'asd' as 'pk', deviceId as PartitionKey
INTO
    [TableApiCosmosDb]
From
    [devicesMessages]

The Special char is the problem.

While create the output with partition as 'id' and while insert query 'deviceId' as PartitionKey, because of that it is not partition correctly.

Example:

SELECT
        id as PartitionKey, SUM(CAST(temperature AS float)) AS temperaturesum ,AVG(CAST(temperature AS float)) AS temperatureavg
INTO streamout
FROM
    Streaminput TIMESTAMP by Time
GROUP BY
     id ,
    TumblingWindow(second, 60)