Capture first character of last group of 1s in a binary series - tsql

Question

I have a series something like this:
Month J F M A M J J A S O N D
Status 1 0 0 1 0 1 0 0 1 1 1 1
Using t-SQL, I am trying to capture the month corresponding to the first 1 in the last group of 1s, i.e., September in this example.
Here is the code I'm using:
IF OBJECT_ID('tempdb..#Temp1') IS NOT NULL DROP TABLE #Temp1
;WITH PARTITIONED1 AS
(SELECT , t0.ID
, t0.Year_Month
, t0.Status
, LAST_VALUE(t0.Year_Month) OVER (PARTITION BY t0.ID ORDER BY t0.Year_Month) AS D_YM
, ROW_NUMBER() OVER (PARTITION BY t0.ID ORDER BY t0.Year_Month) AS rn1
FROM #Temp0 t0
However, this just returns the first occurence of a 1; January here.
I really can't figure this one out, so any help would be very much appreciated.

Answer 1

Carefull with
although the ordering is performed in a previous stage
The previous sorting does not guarantee the later processing!
Try something like this. It is a very simple approach where you rely on gapless IDs:
DECLARE #tbl TABLE(ID INT IDENTITY,Mnth VARCHAR(100),[Status] TINYINT);
INSERT INTO #tbl VALUES
('J',1)
,('F',0)
,('M',0)
,('A',1)
,('M',0)
,('J',1)
,('J',0)
,('A',0)
,('S',1)
,('O',1)
,('N',1)
,('D',1);
SELECT a.*
FROM #tbl AS a
WHERE a.ID=(SELECT MAX(b.ID)+1 FROM #tbl AS b WHERE b.[Status]=0)

Answer 2

this can also be used :
select top 1 Month from table t where Status=1
and not exists
(select id from table t1 where stat=0 and t1.id>t.id)
order by t.id

Answer 3

I might have overcomplicated this but not knowing the table structure I put the below together:
IF OBJECT_ID('tempdb..#Temp1') IS NOT NULL DROP TABLE #Temp1
CREATE TABLE #Temp1
(
Jan int,
Feb int,
Mar int,
Apr int,
May int,
June int,
July int ,
Aug int,
Sep int,
Oct int,
Nov int,
Dec int
)
insert into #temp1
select
1, 0, 0, 1, 0, 1, 0, 0, 1, 1, 1, 1
IF OBJECT_ID('tempdb..#monthTranslate') IS NOT NULL DROP TABLE #monthTranslate
create table #monthTranslate
(
MonthValue varchar(50),
MonthInt int
)
insert into #monthTranslate
select 'Jan',1
union all select 'Feb',2
union all select 'Mar',3
union all select 'Apr',4
union all select 'May',5
union all select 'June',6
union all select 'July',7
union all select 'Aug',8
union all select 'Sep',9
union all select 'OCt',10
union all select 'Nov',11
union all select 'Dec',12
--find the max month w\ 0 and add 1... becareful on null, it might return January incorrectly. I'd check for that in a a case statement
select max(b.MonthInt)+1
from
(
select
MonthPassVal, months , t.MonthInt
from
(
select Jan, Feb, Mar, Apr, May, June, July, Aug, Sep, Oct, Nov, Dec
from #temp1
) as r
Unpivot
(
MonthPassVal for Months
in (Jan, Feb, Mar, Apr, May, June, July, Aug, Sep, Oct, Nov, Dec)
) as u
inner join #monthTranslate t
on t.MonthValue = months
) as b
where
MonthPassVal=0