Declare @s varchar(100),@result varchar(100)
set @s='lkjflkjd-sflsakjqj098yvak8751'
set @result=''
select @result=@result + (case when number like '[0-9]' then number else '' end)
from (select substring(@s,number,1) as number from (select number from master..spt_values where type='p' and number between 1 and len(@s)) as t) as t
select @result as only_numbers
Result:
0988751
