Sum called in two influx instances returns different results

InfluxDB 1
1

I use influx 1.7.8

In two influx instances, I have (I think) the same records. The first influx was created about 4 months ago, and the other one was created a week ago. I migrated data from the first to the other.

When I count records I receive the same number of records.
select count(field1) as res from table1 where time>='2021-12-01 00:00:00' and time<'2021-12-31 00:00:00' group by time(1d)

When I fetch all records from that time I receive the same records.
select field1 as res from table1 where time>='2021-12-01 00:00:00' and time<'2021-12-31 00:00:00'

When I sum the values of fields I received different results.
select sum(field1) as res from table1 where time>='2021-12-01 00:00:00' and time<'2021-12-31 00:00:00' group by time(1d)

There are thousands of records in table ‘table1’.
What causes the problem?
Thanks in advance.

2

Honestly no idea, if the data have been migrated the value should be exactly the same.

I’d try with a different time interval, something like 1h to see if there is apecific interval that differs:

select count(field1),sum(field1) from table1 where time>='2021-12-01 00:00:00' and time<'2021-12-31 00:00:00' group by time(1h)