T-SQL split on delimiter - sql-server

Question

I am working with an employee hierarchy string that is in the format of the following. These number represent employeeID numbers and how the are structured within the company, thus being able to follow the chain of management.
123|456|789|012|345|320
I am trying to take this string of data and turn it into a temp table so I can work with each of the ID's as their own value.
I tried making a function to split the string:
ALTER FUNCTION [dbo].[SplitString]
(#String NVARCHAR(4000),
#Delimiter NCHAR(1))
RETURNS TABLE
AS
RETURN
(WITH Split(stpos, endpos) AS
(
SELECT 0 AS stpos, CHARINDEX(#Delimiter, #String) AS endpos
UNION ALL
SELECT endpos + 1, CHARINDEX(#Delimiter, #String, endpos+1)
FROM Split
WHERE endpos > 0
)
SELECT
'Id' = ROW_NUMBER() OVER (ORDER BY (SELECT 1)),
'Data' = SUBSTRING(#String, stpos, COALESCE(NULLIF(endpos, 0), LEN(#String) + 1))
FROM
Split
)
This however resulted in the following:
Id Data
-------------------
1 123
2 456|7893
3 7893|012|345|
4 012|345|320
5 345|320
6 320
Is there a better way to approach this, maybe not needing a function at all or will it be required to achieve this?

Answer 1

Without a Parse Function
Declare #YourTable table (ID int,IDList varchar(Max))
Insert Into #YourTable values
(1,'123|456|789|012|345|320'),
(2,'123|456')
Select A.ID
,B.*
From #YourTable A
Cross Apply (
Select RetSeq = Row_Number() over (Order By (Select null))
,RetVal = LTrim(RTrim(B.i.value('(./text())[1]', 'varchar(max)')))
From (Select x = Cast('<x>'+ replace((Select A.IDList as [*] For XML Path('')),'|','</x><x>')+'</x>' as xml).query('.')) as A
Cross Apply x.nodes('x') AS B(i)
) B
Returns
ID RetSeq RetVal
1 1 123
1 2 456
1 3 789
1 4 012
1 5 345
1 6 320
2 1 123
2 2 456
OR with the SUPER DUPER Parse (orig source listed below / couple of tweaks)
Select A.ID
,B.*
From #YourTable A
Cross Apply [dbo].[udf-Str-Parse-8K](A.IDList,'|') B
Would Return the same as above
CREATE FUNCTION [dbo].[udf-Str-Parse-8K] (#String varchar(max),#Delimiter varchar(10))
Returns Table
As
Return (
with cte1(N) As (Select 1 From (Values(1),(1),(1),(1),(1),(1),(1),(1),(1),(1)) N(N)),
cte2(N) As (Select Top (IsNull(DataLength(#String),0)) Row_Number() over (Order By (Select NULL)) From (Select N=1 From cte1 a,cte1 b,cte1 c,cte1 d) A ),
cte3(N) As (Select 1 Union All Select t.N+DataLength(#Delimiter) From cte2 t Where Substring(#String,t.N,DataLength(#Delimiter)) = #Delimiter),
cte4(N,L) As (Select S.N,IsNull(NullIf(CharIndex(#Delimiter,#String,s.N),0)-S.N,8000) From cte3 S)
Select RetSeq = Row_Number() over (Order By A.N)
,RetVal = Substring(#String, A.N, A.L)
From cte4 A
);
--Orginal Source http://www.sqlservercentral.com/articles/Tally+Table/72993/
--Much faster than str-Parse, but limited to 8K
--Select * from [dbo].[udf-Str-Parse-8K]('Dog,Cat,House,Car',',')
--Select * from [dbo].[udf-Str-Parse-8K]('John||Cappelletti||was||here','||')
Edit - Stand Alone
Declare #String varchar(max) = '123|456|789|012|345|320'
Declare #Delim varchar(10) = '|'
Select RetSeq = Row_Number() over (Order By (Select null))
,RetVal = LTrim(RTrim(B.i.value('(./text())[1]', 'varchar(max)')))
From (Select x = Cast('<x>'+ replace((Select #String as [*] For XML Path('')),#Delim,'</x><x>')+'</x>' as xml).query('.')) as A
Cross Apply x.nodes('x') AS B(i)

Answer 2

If you need a string "splitter" the fastest one available for 2012 (pre- 2016) is going to be found here. This will blow the doors off of anything posted thusfar. If your items/tokens are all the same size then an even faster method would be this:
DECLARE #yourstring varchar(8000) = '123|456|789|012|345|320';
WITH E(N) AS (SELECT 1 FROM (VALUES (1),(1),(1),(1),(1),(1),(1),(1),(1),(1))t(v)),
iTally(N) AS (SELECT TOP ((LEN(#yourstring)/4)+1) ROW_NUMBER() OVER (ORDER BY (SELECT 1))
FROM e a, e b, e c, e d)
SELECT itemNumber = ROW_NUMBER() OVER (ORDER BY N), item = SUBSTRING(#yourstring, ((N*4)-3), 3)
FROM iTally;
Results:
itemNumber item
-------------------- ----
1 123
2 456
3 789
4 012
5 345
6 320
I write more about this and provide examples of how to put this logic into a function here.

Answer 3

I use this version of the Split function.
CREATE FUNCTION [dbo].[Split]
(
#delimited nvarchar(max),
#delimiter nvarchar(100)
) RETURNS #t TABLE
(
-- Id column can be commented out, not required for sql splitting string
id int identity(1,1), -- I use this column for numbering splitted parts
val nvarchar(max)
)
AS
BEGIN
declare #xml xml
set #xml = N'<root><r>' + replace(#delimited,#delimiter,'</r><r>') + '</r></root>'
insert into #t(val)
select
r.value('.','varchar(max)') as item
from #xml.nodes('//root/r') as records(r)
RETURN
END
You Query would look something like....
SELECT *
FROM TableName t
CROSS APPLY [dbo].[Split](t.EmpIDs, '|')