I would use values instead of list in my stats command:
sourcetype=csv 409,1
| rex field=_raw "(d+,){2}(?<fieldid>d+)"
| rex field=_raw "(d+,){3}(?<headid>d+)"
| rex field=_raw "(d+,){44}(?<head_value>d+)"
| stats values(fieldid) as field_ID, values(headid) as head_ID, sum(head_value) as Value
| eval Parameter = "parameter_1"
| eval hex= "112"
| eval bell_id= "33"
| fields Parameter hex bell_ID field_ID head_ID Value
Also, I don't see a need for the search command - you can put that as part of the first search
But on closer reading, I think this may be what you want:
sourcetype=csv 409,1
| rex field=_raw "(d+,){2}(?<fieldid>d+)"
| rex field=_raw "(d+,){3}(?<headid>d+)"
| rex field=_raw "(d+,){44}(?<head_value>d+)"
| stats sum(head_value) as sumValue by fieldid headid
| stats list(fieldid) as field_ID, list(headid) as head_ID, list(sumValue) as Value
| eval Parameter = "parameter_1"
| eval hex= "112"
| eval bell_id= "33"
| fields Parameter hex bell_ID field_ID head_ID Value
... View more