create range using with cte in sql

Question

I have a table with only single column which have values like as follow

declare @numberrange table 
(
  num int 
)

insert into @numberrange (num) 
 values(24) ,
 (29) ,
( 34 ),
( 39 ),
( 44 ),
( 49 ),
( 54 ),
( 59  ),
( 64  ),
( 69  ),
( 74  ),
( 99 )

Now i want to show the result like as follow

24  24-29
29  30-34
34  35-39
39  40-44
44  45-49
49  50-54
54  55-59
59  60-64
64  65-69
69  70-74
74  75-99
99

i have tried with sql cte function but not able to get the desired result.

Answer 1

You can use this CTE query. The query builds the range from the last record so that the last record has empty range and the first one has a range.

;with cte
as
(
    select top 1 num, sortorder, convert(varchar(21), null) rangevalue
    from (select num, ROW_NUMBER() over (order by num) as sortorder from @numberrange) x
    order by sortorder desc

    union all

    select x.num, x.sortorder, convert(varchar(10), x.num) + '-' + convert(varchar(10), cte.num)
    from (select num, ROW_NUMBER() over (order by num) as sortorder from @numberrange) x
    inner join cte
    on cte.sortorder = x.sortorder + 1
)

select num, rangevalue from cte
order by num