Recursive CTE Pivot for rolling count in SQL Server? - sql

Question

Basically I have a table of membership dates and status changes and I want to create a rolling count of each number of members by status for each date like:
And I want to output it like:
Not really sure on the best way to construct this query I suppose I'd have to create a recursive query to count the events at the date and then pivot the output to create separate columns for the member status?
TIA
create table MyTable(status int,st datetime, memberID int)
insert into MyTable values(1,'2022-02-01',1),
(1,'2022-03-01' ,2),
(2,'2022-04-01',1)
select [st],[1],[2]
from (select [st],memberID,status from MyTable) as SrcTable
pivot(
count(memberID) for status in ([1],[2])
) as pivottable
order by [st] asc
But it doesnt aggregate in March like I want it to

Answer 1

Figured it out I put the last date as get_date() since that what my problem in real-life requires but I did make use of a recursive CTE and pivot
create table MyTable(status int,st datetime, memberID int)
insert into MyTable values(1,'2022-02-01',1),
(1,'2022-03-01' ,2),
(2,'2022-04-01',1);
with cte as (
select status,st,memberID,(case when Nxt_sts is null then 0 else Nxt_sts end)
as Nxt_sts,
(case when Nxt_st is null then FORMAT(DateAdd(Month,1,getdate()), 'yyyyMM01')
else Nxt_st end) as Nxt_st
from (select
A.status,A.st,A.memberID,B.status as Nxt_sts,B.st as nxt_st
from MyTable A
left join MyTable B
on A.MemberID = B.MemberID
and A.status+1 = B.status ) A
)
, cte_2 as
(
select status,st,memberID,Nxt_sts,Nxt_st
from cte
Union All
select status,DateAdd(Month, 1 ,st),memberID,Nxt_sts,Nxt_st from cte_2
where DateAdd(Month, 1 ,st) < Nxt_st
)
select [st],[1],[2],[3]
from (select [st],memberID,status from cte_2) as SrcTable
pivot(
count(memberID) for status in ([1],[2],[3])
) as pivottable
order by [st] asc