TSQL - Split delimited String into columns - sql-server

Question

The Problem
I have a number of filename strings that I want to parse into columns using a tilda as delimiter. The strings take on the static format:
Filepath example C:\My Documents\PDF
Surname example Walker
First Name example Thomas
Birth Date example 19991226
Document Created Datetime example 20180416150322
Document Extension example .pdf
So a full concatenated example would be something like:
C:\My Documents\PDF\Walker~Thomas~19991226~20180416150322.pdf
I want to ignore the file path and extension given in the string and only parse the following values into columns:
Surname, First Name, Birth Date, Document Created Datetime
So something like:
SELECT Surname = --delimitedString[0]
FirstName = --delimitedString[1]
--etc.
What I have tried
I know that I have several tasks I would need to perform in order to split the string, first I would need to trim off the extension and file path so that I can return a string delimited by tildas (~).
This is problem one for me, however problem 2 is splitting the new delimted string itself i.e.
Walker~Thomas~19991226~20180416150322
Ive had a good read through this very comprehensive question and It seems (as im using SQL Server 2008R2) the only options are to use either a function with loops or recursive CTE's or attempt a very messy attempt using SUBSTRING() with charIndex().
Im aware that If I had access to SQL Server 2016 I could use string_split but unfortunately I cant upgrade.
I do have access to SSIS but im very new to it so decided to attempt the bulk of the work within a SQL statement

Answer 1

Here is a way without a splitter that shouldn't be too complicated...
declare #var table (filepath varchar(256))
insert into #var values
('C:\My Documents\PDF\Walker~Thomas~19991226~20180416150322.pdf')
;with string as(
select
x = right(filepath,charindex('\',reverse(filepath))-1)
from #var
)
select
SurName= substring(x,1,charindex('~',x) - 1)
,FirstName = substring(x,charindex('~',x) + 1,charindex('~',x) - 1)
from string

Answer 2

I know you mentioned wanting to avoid the charindex() option if at all possible, but I worked it out in a hopefully semi-readable way. I find it somewhat easy to read complex functions like this when I space each parameter on a different line and use indent levels. It's not the most proper looking, but it helps with legibility:
with string as (select 'C:\My Documents\PDF\Walker~Thomas~19991226~20180416150322.pdf' as filepath)
select
substring(
filepath,
len(filepath)-charindex('\',reverse(filepath))+2, --start location, after last '\'
len(filepath)- --length of path
(len(filepath)-charindex('\',reverse(filepath))+2)- --less characters up to last '\'
(len(filepath)-charindex('.',filepath)) --less file extention
)
from string

Answer 3

Fritz already have a great start, my answer just add on top it
with string as (select 'C:\My Documents\PDF\Walker~Thomas~19991226~20180416150322.pdf' as filepath)
, newstr as (
select
REPLACE(substring(
filepath,
len(filepath)-charindex('\',reverse(filepath))+2, --start location, after last '\'
len(filepath)- --length of path
(len(filepath)-charindex('\',reverse(filepath))+2)- --less characters up to last '\'
(len(filepath)-charindex('.',filepath)) --less file extention
) , '~', '.') as new_part
from string
)
SELECT
PARSENAME(new_part,4) as Surname,
PARSENAME(new_part,3) as [First Name],
PARSENAME(new_part,2) as [Birth Date],
PARSENAME(new_part,1) as [Document Created Datetime]
FROM newstr