Put value in minimum ID record in SQL data set - sql

Question

I have a table where I'm trying to get the following result: CategoryType should be set to 0 for the member record with the lowest categoryID and 1 if that ID is NULL. CategoryType is not a field from the table so it should be added via a Case statement. I wrote a script using the Row_Number() window function to organize the records but I'm not sure how to put a 0 for the lowest record. I tried using a Min(Case) statement but that didn't work.
declare #t table(memberid int, lastname varchar(50), firstname varchar(50), categoryid int)
insert into #t
values(1, 'Jones', 'Tom', 2), (1, 'Jones', 'Tom', 4),
(2, 'Hanson', 'Ron', 3), (2, 'Hanson', 'Ron', 4),
(2, 'Hanson', 'Ron', 5),
(3, 'Smith', 'Jack', NULL);
This is the result I'm trying to get:
MemberID LastName FirstName CategoryID CategoryType
1 Jones Tom 2 0
1 Jones Tom 4 NULL
2 Hanson Ron 3 0
2 Hanson Ron 4 NULL
2 Hanson Ron 5 NULL
3 Smith Jack NULL 1

Answer 1

Or this:
select *
,case
when categoryid is null then 1
when FIRST_VALUE(categoryid) over (partition by memberid order by categoryid) = categoryid then 0 else null
end as x
from #t

Answer 2

I think you want this
SELECT *,CASE WHEN categoryid IS NULL THEN 1
WHEN ROW_NUMBER() OVER (PARTITION BY categoryid ORDER BY memberid) = 1
THEN 0
END CategoryType FROM #T

Answer 3

Easier to read/extend (if needed):
SELECT a.MemberID,a.LastName,a.FirstName,a.CategoryID
,CASE
WHEN a.rn = 1 AND a.CategoryID IS NULL THEN 1
WHEN a.rn = 1 THEN 0
ELSE NULL
END AS [CategoryType]
FROM (
SELECT t.MemberID,t.LastName,t.FirstName,t.CategoryID
,ROW_NUMBER()OVER(PARTITION BY t.MemberID ORDER BY t.CategoryID) AS [rn]
FROM #t t
) a
;

Answer 4

I think you want:
select t.*,
(case when categoryid is null
then 1
when row_number() over (partition by memberid order by categoryid) = 1
then 0
end) as categorytype
from #t t;
Here is a db<>fiddle.

Answer 5

Hope Can Help You
declare #t table(memberid int,
lastname varchar(50),
firstname varchar(50),
categoryid int)
insert into #t
values(1, 'Jones', 'Tom', 2),
(1, 'Jones', 'Tom', 4),
(2, 'Hanson', 'Ron', 3),
(2, 'Hanson', 'Ron', 4),
(2, 'Hanson', 'Ron', 5),
(3, 'Smith', 'Jack', NULL)
Select
A.*,
Case When a.categoryid is null Then '1'
When b.categoryid is not null Then '0' Else null End CategoryType
From #t A
Left Join (
Select memberid, min(categoryid) categoryid From #t
Group By memberid
) B On B.memberid = A.memberid and B.categoryid = A.categoryid