How to pick Max value of SQL Output - sql

Question

SQL Query Syntax issue. I have a query which returns around 150,000 rows of records. In this query, you can see ROW_NUMBER() OVER PARTITION. On select * from cte, I need to pick only the highest value of ROW_NUMBER() for each Pat_id.
If RowNumber is 150 for one pat_id. I need only that row of records. I am having difficult in narrowing down to one record. I request experts to share your syntax to help me.
with cte
as (
select pat.pat_id,
pat.fname as [FirstName],
pat.mname as [MiddleName],
pat.lname as [LastName],
[DOB] =Convert(VARCHAR(12),pat.birth_date,101),
csc.name as [AccountType],
[Plan Name] = CASE when (isnull(org.name,'')='') then 'CASH' else org.name end
,cprx_disp.disp_days_supply
,cprx_disp.dispense_date
,(cprx_disp.dispense_date + cprx_disp.disp_days_supply) as [DateDue]
,ROW_NUMBER() over(PARTITION BY pat.pat_id ORDER BY cprx_disp.dispense_date) as [RowNumber]
From cppat pat (nolock)
left outer join cppat_ins patins(NoLock) ON patins.pat_id = pat.pat_id
left outer join csorg org on org.org_id = patins.org_id
inner join csct_code csc on pat.pat_type_cn = csc.code_num
join cprx on cprx.pat_id = pat.pat_id
join cprx_disp (nolock) on cprx.last_rxdisp_id = cprx_disp.rxdisp_id
where csc.ct_id = 163
and csc.code_num in (1033,1010,1011,1012,1016,1017,1016,1018)
and patins.status_cn = 1
and patins.priority = 1
-- Commented.
-- and pat.pat_id = 2561
)
select cte.[FirstName],
cte.[MiddleName],
cte.[LastName],
cte.[DOB],
cte.[AccountType],
cte.[Plan Name],
Cte.DateDue
from cte

Answer 1

Well, you're not actually using the RowNumber in the output, so I would just reverse it and then return those that equal 1:
with cte
as (
select pat.pat_id,
pat.fname as [FirstName],
pat.mname as [MiddleName],
pat.lname as [LastName],
[DOB] =Convert(VARCHAR(12),pat.birth_date,101),
csc.name as [AccountType],
[Plan Name] = CASE when (isnull(org.name,'')='') then 'CASH' else org.name end
,cprx_disp.disp_days_supply
,cprx_disp.dispense_date
,(cprx_disp.dispense_date + cprx_disp.disp_days_supply) as [DateDue]
,ROW_NUMBER() over(PARTITION BY pat.pat_id ORDER BY cprx_disp.dispense_date DESC) as [RowNumber]
from cppat pat (nolock)
left outer join cppat_ins patins(NoLock) on patins.pat_id = pat.pat_id
left outer join csorg org on org.org_id = patins.org_id
inner join csct_code csc on pat.pat_type_cn = csc.code_num
join cprx on cprx.pat_id = pat.pat_id
join cprx_disp (nolock) on cprx.last_rxdisp_id = cprx_disp.rxdisp_id
where csc.ct_id = 163
and csc.code_num in (1033,1010,1011,1012,1016,1017,1016,1018)
and patins.status_cn = 1
and patins.priority = 1
-- Commented.
-- and pat.pat_id = 2561
)
select cte.[FirstName],
cte.[MiddleName],
cte.[LastName],
cte.[DOB],
cte.[AccountType],
cte.[Plan Name],
cte.DateDue
from cte
WHERE RowNumber = 1;