I have already posted two posts about extracting numbers from a string

http://beyondrelational.com/blogs/madhivanan/archive/2007/12/18/extract-only-numbers-from-a-string.aspx
http://beyondrelational.com/blogs/madhivanan/archive/2010/04/22/extracting-numbers-part-2.aspx

Loana in her blog posted a post about extracting integers from a string. Common table expression is used in the post. Here is an alternate that uses a user defined function.

Sample data

DECLARE @sample TABLE(
                      id INT,    
                      data VARCHAR(200) ) 
INSERT @sample
       SELECT 1, 'bar 1245 foo' UNION ALL
       SELECT 2, 'foo 35234 bar 38383 fgh gaaaaaaaaa 84' UNION ALL
       SELECT 3, 'bar 126831' UNION ALL
       SELECT 4, '72348707 foo' UNION ALL
       SELECT 5, 'foo bar';

Function which splits the data based on the delimiter

create function split(@data varchar(200),@delimiter char(1))
returns @splitting table (id int identity(1,1), data varchar(200))
as
begin

select @delimiter=replace(@delimiter,' ',','), @data=replace(@data,' ',',')
insert into @splitting(data) 
select 
    substring(@data, n, charindex(@delimiter, @data + @delimiter, n ) - n) 
from 
    ( 
        select number as n from master..spt_values
		where type='p' 
    ) numbers 
where 
    substring( @delimiter + @data, n, 1 ) = @delimiter
return
end

SELECT statement that concatenates the numbers

SELECT distinct
      id, STUFF((SELECT 
                       ', ' + sp.data 
                 FROM 
                      @sample samp cross apply dbo.split(data,' ') as sp
				where sp.data not like '%[^0-9]%' and samp.id=t1.id
                 FOR XML PATH('')), 1, 2, '' ) AS numbers 
FROM 
    @sample as t1

The function is used to split the string and the condition used in the SELECT statement where sp.data not like '%[^0-9]%' is used to find only the numbers from the splitted string