Hierarchical sorting in sql server when child identifier contains "."

Question

I have some children below

childid
------------

1.1
1.2
2.8
2.7
6.5
6.5.1
6.5.15
7.1
8

sort order will be

childid 
--------
1.1
1.2
2.7
2.8
6.5
6.51
6.5.15
7.1

I tried to convert to intiger as below

declare @str nvarchar(max)='1.23.2';

set @str=(select replace(@str,'.',''))
select @str

but he fails if

7.1
8

comes he gives such an order as

8
7.1 

but i need order as below

7.1
8

also if a number like

7.1.1
7.1.8
6.7.7.7

then the order should be

6.7.7.7
7.1.1
7.1.8

Hope someone can help me solve this problem.

Answer 1

Try the following:

EDIT: I changed the approach to deal with non-numeric values ​​like "123abc".

declare @ids table(idList varchar(100))
insert into @ids values
 ('1.1')
,('1.2')
,('2.8')
,('2.7')
,('6.5')
,('6.5.1')
,('6.5.15')
,('7.1')
,('8');

select idList,padded.OrderBy
from @ids as ids
cross apply(select cast('<r>' + replace(idList,'.','</r><r>') + '</r>' as xml)) as AsXml(val)
cross apply
(
    select right('                ' + rtrim(x.y.value('.','varchar(max)')),10) 
    from AsXml.val.nodes('/r') as x(y)
    for xml path('')
) as padded(OrderBy)
order by padded.OrderBy

Answer 2

Not an elegant solution, but it works for me:

DECLARE @t TABLE ( childid VARCHAR(100) )
INSERT  INTO @t
VALUES  ( '1.1' ),
        ( '1.2' ),
        ( '2.8' ),
        ( '2.7' ),
        ( '6.5' ),
        ( '6.5.1' ),
        ( '6.5.15' ),
        ( '7.1' ),
        ( '8' )

;WITH cte AS(SELECT childid + '.' AS childid FROM @t)
SELECT LEFT(childid, LEN(childid) - 1) AS childid
FROM cte
CROSS APPLY(SELECT CHARINDEX('.', childid) i1) c1
CROSS APPLY(SELECT CASE WHEN i1 = 0 THEN 0 ELSE CHARINDEX('.', childid, i1 + 1) END i2) c2
CROSS APPLY(SELECT CASE WHEN i2 = 0 THEN 0 ELSE CHARINDEX('.', childid, i2 + 1) END i3) c3
CROSS APPLY(SELECT CASE WHEN i3 = 0 THEN 0 ELSE CHARINDEX('.', childid, i3 + 1) END i4) c4
CROSS APPLY(SELECT CASE WHEN i4 = 0 THEN 0 ELSE CHARINDEX('.', childid, i4 + 1) END i5) c5
ORDER BY
        CASE WHEN i1 = 0 THEN childid ELSE SUBSTRING(childid, 1, i1 - 1) END,
        CASE WHEN i2 = 0 THEN '0' ELSE SUBSTRING(childid, i1 + 1, i2 - i1 - 1) END,
        CASE WHEN i3 = 0 THEN '0' ELSE SUBSTRING(childid, i2 + 1, i3 - i2 - 1) END,
        CASE WHEN i4 = 0 THEN '0' ELSE SUBSTRING(childid, i3 + 1, i4 - i3 - 1) END,
        CASE WHEN i5 = 0 THEN '0' ELSE SUBSTRING(childid, i4 + 1, i5 - i4 - 1) END

cross apply . , , cross applies, .