Select row satisfying certain condition and rows next to it - sql-server

Question

Let's say I have a historical table keeping who has modified data
-------------------------------------------------------------
| ID | Last_Modif | User_Modif | Col3, Col4...
-------------------------------------------------------------
| 1 | 2018-04-09 12:12:00 | John
| 2 | 2018-04-09 11:10:00 | Jim
| 3 | 2018-04-09 11:05:00 | Mary
| 4 | 2018-04-09 11:00:00 | John
| 5 | 2018-04-09 10:56:00 | David
| 6 | 2018-04-09 10:53:00 | John
| 7 | 2018-04-08 19:50:00 | Eric
| 8 | 2018-04-08 18:50:00 | Chris
| 9 | 2018-04-08 15:50:00 | John
| 10 | 2018-04-08 12:50:00 | Chris
----------------------------------------------------------
I would like to find the modifs done by John and previous version before he did that, to check what he had modified. For example in this scenario I would like to return row 1,2,4,5,6,7,9,10
I am thinking of ranking first based on Last_modif then do a join to pick up the next row, but somehow the result is not correct. This seems not a LAG/LEAD case since I am not picking a single value from the next row, but instead the whole next row. Any idea ?
-- sample 1000 rows with RowNumber
with TopRows as
(select top 1000 *, ROW_NUMBER() OVER(ORDER BY Last_modif desc) RowNum from [Table])
--Reference rows : Rows modif by John
, ModifByJohn as
(Select * from TopRows where USER_MODIF = 'John')
select * from ModifByJohn
UNION
select ModifByNext.* from ModifByJohn join TopRows ModifbyNext on ModifByJohn.RowNum + 1 = ModifByNext.RowNum
order by RowNum
How will the code look like if we would like to return last 2 modifs before John did instead of 1 ?

Answer 1

Maybe you can take advantage of your current ID:
with x as
(
select t1.*,
(select top 1 id from tbl where id > t1.id) prev_id
from tbl t1
where t1.User_Modif = 'John'
)
select * from x;
GO
ID | Last_Modif | User_Modif | prev_id
-: | :------------------ | :--------- | ------:
1 | 09/04/2018 12:12:00 | John | 2
4 | 09/04/2018 11:00:00 | John | 5
6 | 09/04/2018 10:53:00 | John | 7
9 | 08/04/2018 15:50:00 | John | 10
with x as
(
select t1.*,
(select top 1 id from tbl where id > t1.id) prev_id
from tbl t1
where t1.User_Modif = 'John'
)
select ID, Last_Modif, User_Modif from x
union all
select ID, Last_Modif, User_Modif
from tbl
where ID in (select prev_id from x)
order by ID
GO
ID | Last_Modif | User_Modif
-: | :------------------ | :---------
1 | 09/04/2018 12:12:00 | John
2 | 09/04/2018 11:10:00 | Jim
4 | 09/04/2018 11:00:00 | John
5 | 09/04/2018 10:56:00 | David
6 | 09/04/2018 10:53:00 | John
7 | 08/04/2018 19:50:00 | Eric
9 | 08/04/2018 15:50:00 | John
10 | 08/04/2018 12:50:00 | Chris
dbfiddle here