$__timegroup returns multiple records but in db it's have only one record

SELECT
$__timeGroup(“tm”, $__interval, 0) as “time”,
AVG(“hist”) as “History”
FROM
historicalavgmultiple(’${MultiDeviceId:glob}’)
GROUP BY 1
ORDER BY 1

the above query returns 168 records but i run this query in psql terminal but it returns only one record, and the result was not good please help to resolve this issue.

anyone please reply for this question ?