Having clause being ignored - sql

Question

In this query, I am attempting to get a count that gives me a count of patients for each practice under given conditions.
The issue is that I have to show patients who have had >=3 office visits in the past year.
Count(D.PID)
in the select list is ignoring
HAVING count(admitdatetime)>=3
Here is my query
select distinct D.PracticeAbbrevName, D.ProviderLastName, count(D.pid) AS Count
from PersonDetail AS D
left join Visit AS V on D.PID = V.PID
where D.A1C >=7.5 and V.admitdatetime >= (getdate()-365) and D.A1CDays <180 and D.Diabetes = 1
group by D.PracticeAbbrevName, D.ProviderLastName
having count(admitdatetime)>=3
order by PracticeAbbrevName
If I get rid of the count function for D.pid, and just display each PID individually, my having phrase works properly.
There is something about count and having that do now work properly together.

Answer 1

Revised answer:
SELECT DISTINCT
D.PracticeAbbrevName,
D.ProviderLastName,
COUNT(D.pid) AS PIDCount,
COUNT(admitdatetime) AS AdmitCount
FROM
PersonDetail AS D
LEFT JOIN Visit AS V
ON D.PID = V.PID
WHERE
D.A1C >= 7.5
AND V.admitdatetime >= ( GETDATE() - 365 )
AND D.A1CDays < 180
AND D.Diabetes = 1
GROUP BY
D.PracticeAbbrevName,
D.ProviderLastName
HAVING
COUNT(admitdatetime) >= 3
ORDER BY
PracticeAbbrevName

Answer 2

You're trying to do too much at once. Split the logic in 2 steps:
Query grouping by PID to filter out patients that don't meet your criteria.
Query grouping by practice to get a patient count.
Your query would look like this:
;with EligiblePatients as (
select d.pid,
d.PracticeAbbrevName,
d.ProviderLastName
from PersonDetail d
left join Visit v
on v.pid = d.pid
and v.admitdatetime >= (getdate()-365)
where d.A1C >= 7.5
and d.A1CDays < 180
and d.Diabetes = 1
group by d.pid,
d.PracticeAbbrevName,
d.ProviderLastName
having count(v.pid) >= 3
)
select PracticeAbbrevName,
ProviderLastName,
COUNT(*) as PatientCount
from EligiblePatients
group by PracticeAbbrevName,
ProviderLastName
order by PracticeAbbrevName