Selecting all rows conditionally between 2 arbitrary column values in SQL Server - sql

Question

I've joined a number of tables to get to this table. From this table I need to select all of the b_id values that fall between the start end end values that are not null. There could be multiple start and end values in the table. How can I write a SQL Server query to select all of the b_ids between but not including those rows. So for this example table I would need the b_ids 99396 AND 71828
I tried to find a similar question and found something like this but I don't believe I'm using the correct values where they need to be. Is there another way to do it. I have a solution using a cursor, but I'm trying to find a non cursor solution. My friend told me the responses on here can be brutal if you don't word the question a certain way. Please be easy on me lol.
a_id | b_id | sequence | start | end |
---------+-------+----------+-------+-------+
3675151 | 68882 | 1 | null | null |
3675151 | 79480 | 2 | 79480 | null |
3675151 | 99396 | 3 | null | null |
3675151 | 71828 | 4 | null | null |
3675151 | 28911 | 5 | null | 28911 |
3675151 | 27960 | 6 | null | null |
3675183 | 11223 | 1 | null | null |
3675183 | 77810 | 2 | null | null |
3675183 | 11134 | 3 | null | null |
3675183 | 90909 | 4 | null | null |

Answer 1

Is this what you are looking for
select a_id, b_id, sequence
from
table
where
(a_id,sequence )
in
(select a_id, sequence from table t1
where
sequence >
(select sequence from table t2 where t1.a_id = t2.a_id and start is not null)
and
sequence <
(select sequence from table t3 where t1.a_id = t3.a_id and end is not null)
);

Answer 2

Would it be this?
Mark as answer if yes, if not exemplify otherwise.
create table #table (
a_id int
,b_id int
,c_sequence int
,c_start int
,c_end int
)
insert into #table
values
(3675151 ,68882 , 1 , null , null )
,(3675151 ,79480 , 2 , 79480 , null )
,(3675151 ,99396 , 3 , null , null )
,(3675151 ,71828 , 4 , null , null )
,(3675151 ,28911 , 5 , null , 28911)
,(3675151 ,27960 , 6 , null , null )
,(3675183 ,11223 , 1 , null , null )
,(3675183 ,77810 , 2 , 4343 , null )
,(3675183 ,11134 , 3 , null , null )
,(3675183 ,90939 , 4 , null , 1231 )
select
t.*
from #table t
where
exists (select t1.b_id,t1.c_sequence
from #table t1
where t1.c_start is not null
and t.a_id =t1.a_id and t.c_sequence>t1.c_sequence )
and exists (select t1.b_id,t1.c_sequence
from #table t1
where t1.c_end is not null
and t.a_id =t1.a_id
and t.c_sequence<t1.c_sequence

Answer 3

You can use window functions for this:
select t.*
from (select t.*,
max(case when c_start is not null then c_sequence end) over (partition by a_id order by c_sequence) as last_c_start,
max(case when c_end is not null then c_sequence end) over (partition by a_id order by c_sequence) as last_c_end,
min(case when c_end is not null then c_sequence end) over (partition by a_id order by c_sequence desc) as next_c_end
from t
) t
where c_sequence > last_c_start and
c_sequence < next_c_end and
(last_c_start > last_c_end or last_c_end is null);
Here is a db<>fiddle.
The subquery is returning the previous start and next end. That is pretty simply. The where uses this information. The last condition just checks that the most recent "start" is the one that should be considered.
Note: This does not handle more complicated scenarios like start-->start-->end-->end. If that is a possibility, you should ask another question.
EDIT:
Actually, there is an even easier way:
select t.*
from (select t.*,
count(coalesce(c_start, c_end)) over (partition by a_id order by c_sequence) as counter
from t
) t
where c_start is null and c_end is null and
counter % 2 = 1;
This returns rows where there two values are NULL (to avoid the endpoints) and there are an odd number of non-NULL c_start/c_end values up to that row.