How to make a range series in SQL - sql

Question

I have to improve a Stored Procedure, it uses a select query on a table as follows:
SELECT DISTINCT ProjectId FROM Project where Status ='P' Order by ProjectId
it give an output as follows:
1
2
3
7
8
11
12
13
I need to use these values in insert statement for another table as follow:
insert into Table values (othervalue, 1|1);
insert into Table values (othervalue, 2|2);
....
To decrease the number of inserts, we want to store as follows:
insert into Table values (othervalue, 1|3);
insert into Table values (othervalue, 7|8);
insert into Table values (othervalue, 11|13);
That is in range till the time there is no gap. I tried using CURSOR to loop through the resultset and have some logic to convert it and keep on inserting. But seems some error.
Can we do something in SELECTquery itself?

Answer 1

with t(a,en,bg) as
(
select a,case when [begin] is NULL then NULL else row_number() over(partition by [begin] order by a) end
,case when [end] is NULL then NULL else row_number() over(partition by [end] order by a) end
from (
select t.a, case when t1.a is NULL then 'end' else NULL end [end],
case when t2.a is NULL then 'begin' else NULL end [begin]
from Project as t left join Project as t1 on (t1.a=t.a+1 AND t.Status='P' AND t1.Status='P')
left join Project as t2 on (t2.a=t.a-1 AND t2.Status='P')
) as o )
select cast(t1.a as varchar)+'|'+cast(t.a as varchar) from t inner join t as t1 on t.en=t1.bg
This query will return you values from Project in '1|3' type.
It's not clear from your question whether you use plsql or sql-server. My solution will be work for MS SQL Server