Count (distinct ...) in SQL

One patient in multiple programs, timeIds,...

You might could do something like:
SELECT PayorID, PayorName, ..... SELECT A.* FROM ((your other count query here)A), ...

Not sure if that will work or not.

Please describe for us what you want in the Patcount column. Assuming the overall SELECT-INTO query is going to insert multiple rows, do you want Patcount to have the same value in each row, that is, the total of distinct patientid's without any conditions?

If so, try this:
SELECT  PayorID, PayorName, LOBPAYOR, Program, PayorTypeCd, AccountTypeCd, Activity_Flag,
 (SELECT count(distinct PatientId) FROM dbo.FACT_ETMI_monthly_Datamart_PC1) as Patcount,
 Activity_Name,  Time_id, the_month, acuityflag
INTO dbo.FACT_ETMI_monthly_Datamart_PC
FROM   dbo.FACT_ETMI_monthly_Datamart_PC1
ORDER BY PayorName, time_id, LOBPAYOR, Program, Activity_Flag,AcuityFlag

If not, we need more explanation as to your goal.

I am not sure you want count halves of patients, but maybe.

if

PayorID, PayorName, LOBPAYOR, Program, PayorTypeCd,AccountTypeCd, Activity_Flag, Activity_Name,  Time_id, the_month, acuityflag
columns are not null

then (else you must set ANSI_NULLS off or rewrite ON clause)
-------------------------------------------------------------------------------------------------------------------------------------------

SELECT  PayorID, PayorName, LOBPAYOR, Program, PayorTypeCd, AccountTypeCd, Activity_Flag, count(distinct A.PatientId)/Cnt as Patcount
, Activity_Name,  Time_id, the_month, acuityflag
INTO dbo.FACT_ETMI_monthly_Datamart_PC
FROM   dbo.FACT_ETMI_monthly_Datamart_PC1 A
JOIN
(
select PatientId,cast(count(*) as float) Cnt from (
SELECT  PayorID, PayorName, LOBPAYOR, Program, PayorTypeCd, AccountTypeCd, Activity_Flag, Activity_Name,  Time_id, the_month, acuityflag
, PatientId
FROM   dbo.FACT_ETMI_monthly_Datamart_PC1
GROUP BY PayorID, PayorName, LOBPAYOR, Program, PayorTypeCd,AccountTypeCd, Activity_Flag, Activity_Name,  Time_id, the_month, acuityflag
) X
) B
ON
    A.PayorID=B.PayorID
AND A.PayorName=B.PayorName
AND A.LOBPAYOR=B.LOBPAYOR
AND A.Program=B.Program
AND A.PayorTypeCd=B.PayorTypeCd
AND A.AccountTypeCd=B.AccountTypeCd
AND A.Activity_Flag=B.Activity_Flag
AND A.Activity_Name=B.Activity_Name
AND A.Time_id=B.Time_id
AND A.the_month=B.the_month
AND A.acuityflag=B.acuityflag
GROUP BY PayorID, PayorName, LOBPAYOR, Program, PayorTypeCd, AccountTypeCd, Activity_Flag, Activity_Name,  Time_id, the_month, acuityflag
ORDER BY PayorName, time_id, LOBPAYOR, Program, Activity_Flag,AcuityFlag

What I realized is that ispaleny was correct, there were patients in more than one program ... which is impossible.  The person who wrote the original query is helping to eliminate those duplicates.  I'm going to leave it open for another day to make sure that I don't need to eliminate the dupes myself (in which case I'll figure out what I need and come back here) but otherwise I'll give the points to ispaleny.  Thanks so much.  :)

Is your column called distinct PatientId? if no then you do it as below,
SELECT  PayorID, PayorName, LOBPAYOR, Program, PayorTypeCd,
                      AccountTypeCd, Activity_Flag, count(distinct (PatientId)) as Patcount......

Sorry.........I stupidly thought..................ok
see this

select count (PatientId) as Patcount , PayorID, PayorName, LOBPAYOR, Program, PayorType, AccountTypeCd, Activity_Flag, PatientId , Activity_Name,  Time_id, the_month, acuityflag
INTO dbo.FACT_ETMI_monthly_Datamart_PC
FROM   dbo.FACT_ETMI_monthly_Datamart_PC1 where PatientId in (SELECT distinct PatientId FROM   dbo.FACT_ETMI_monthly_Datamart_PC1)
GROUP BY PayorID, PayorName, LOBPAYOR, Program, PayorTypeCd,
AccountTypeCd, Activity_Flag, Activity_Name,  Time_id, the_month, acuityflag
ORDER BY PayorName, time_id, LOBPAYOR, Program, Activity_Flag,AcuityFlag