My apologies if I was out of line earlier, somehow I get kind of agitated when requirements focus more on HOW than WHAT, especially when it's incorrect.

The problem itself is elementary, sequential self-join or Lead/Lag on 2012 and later, hence the question about the Version/Edition.

😎

USE tempdb;

GO

create table #table1(steps int)

insert into #table1(steps)values(1)

insert into #table1(steps)values(2)

insert into #table1(steps)values(3)

insert into #table1(steps)values(4)

insert into #table1(steps)values(5)

insert into #table1(steps)values(6)

insert into #table1(steps)values(7)

insert into #table1(steps)values(9)

insert into #table1(steps)values(10)

insert into #table1(steps)values(17)

insert into #table1(steps)values(31)

;WITH BASE_DATA AS

(

select

ROW_NUMBER() OVER (ORDER BY T.steps) AS T_RID

,T.steps

from #table1 T

)

SELECT

B_FROM.steps AS stepFrom

,B_TO.steps AS stepTo

FROM BASE_DATA B_FROM

INNER JOIN BASE_DATA B_TO

ON B_FROM.T_RID = B_TO.T_RID - 1

DROP TABLE #table1;

/* Window Function 2012 */

SELECT

X.stepFrom

,X.stepTo

FROM

(

SELECT

steps AS stepFrom

,LEAD(steps,1) OVER (ORDER BY steps) AS stepTo

FROM #table1

) AS X

WHERE X.stepTo IS NOT NULL;

Results

stepFrom stepTo

----------- -----------

1 2

2 3

3 4

4 5

5 6

6 7

7 9

9 10

10 17

17 31

Edit: forgot the Lead version