Log_agent contains the user that CREATED the ticket, not the one who modified it.
The field that contains the last person who modified it is : last_mod_by.
But in your case it may not be suitable.
What you need to understand is that the information you want is in a related table. Relation is 1 to N wich means that an incident may be related to several activities and one activity is related to one and only one incident.
When you query the ticket table and join it to the activity table, you may have a couple of activity per ticket. This is what you consider as a duplicate. But this is absolutely not a duplicate.
If you want to retrieve the user that closed a ticket, you need to add a condition on the activity type, wich is 'CL' for close. Please note that if the ticket has been closed several times you will have multiple rows for this particular ticket.
Otherwise, you can create a field in the REQUEST table in Xtraction and as the expression set this :
(select COALESCE(cnt.last_name,'n/a') + ',' + COALESCE(cnt.first_name,'n/a')
from (select call_req_id, analyst, type,row_number() over(order by id desc) as rn
from act_log
where act_log.type='CL' and call_Req_id= CR.persid) alg
inner join ca_contact cnt
on cnt.contact_uuid=alg.analyst where rn=1)
You can try this query by running this is your SQL tools :
select top 10000
ref_num,
(select COALESCE(cnt.last_name,'n/a') + ',' + COALESCE(cnt.first_name,'n/a')
from (select
call_req_id,
analyst,
type,
row_number() over(order by id desc) as rn
from act_log where act_log.type='CL' and call_Req_id= CR.persid) alg
inner join ca_contact cnt
on cnt.contact_uuid=alg.analyst where rn=1) as done_by
from call_Req CR
The "row_number" part purpose is to select the last close activity when there is multiple closure.