Getting numeric or character values from an alphanumeric string

Sometimes it becomes necessary to get all the numeric or all the character values from a alphanumeric string.
The idea in the solution I have posted is to convert all the characters from the string into rows in a derived table
using a look table @tbl & then concating the charater values excluding the numeric values in my example below.
If you need to get the numeric values from the string simply replace like '[a-z]' to like '[0-9]'

Declare @str As Varchar(50)
Select @str='klasdjfkl034ioerut'
Declare @value As Varchar(40)=''

Declare @tbl As Table(number Int Identity)
Insert Into @tbl Default Values
While SCOPE_IDENTITY()< len(@str)
Insert Into @tbl Default Values

Select @value=@value + '' + value From
(
Select number,SUBSTRING(@str,number,1)As value From @tbl Where number Between 1 And LEN(@str)
)t Where value like '[a-z]'

Select @value