T-SQL split string by - and space - tsql

Question

I'm having difficult time with T-SQL and I was wondering if somebody could me point me to the right track.
I have the following variable called #input
DECLARE #input nvarchar(100);
SET #input= '27364 - John Smith';
-- SET #input= '27364 - John Andrew Smith';
I need to split this string in 3 parts (ID,Firstname and LastName) or 4 if the string contains a MiddleName. For security reason I cannot use functions.
My aproach was use Substring and Charindex.
SET #Id = SUBSTRING(#input, 1, CASE CHARINDEX('-', #input)
WHEN 0
THEN LEN(#input)
ELSE
CHARINDEX('-', #input) - 2
END);
SET #FirstName = SUBSTRING(#input, CASE CHARINDEX(' ', #input)
WHEN 0
THEN LEN(#input) + 1
ELSE
CHARINDEX(' ', #input) + 1
END, 1000);
SET #LastName = SUBSTRING(#input, CASE CHARINDEX(' ', #input)
WHEN 0
THEN LEN(#input) + 1
ELSE
CHARINDEX('0', #input) + 1
END, 1000);
Select #PartyCode,#FirstName,#LastName
I am stuck because I don't know how to proceed and also the code has to be smart enough to add a fourth split if Middlename exists.
Any thoughts?
Thanks in advance

Answer 1

Hopefully this is part of a normalization project. This data is breaking 1NF and one really should avoid that...
Try it like this
The advantages
typesafe values
ad-hoc SQL
set based
If you want you might use a CASE WHEN to check if the last part is NULL and place Part2 into Part3 in this case...
DECLARE #input table(teststring nvarchar(100));
INSERT INTO #input VALUES
(N'27364 - John Smith'),(N'27364 - John Andrew Smith');
WITH Splitted AS
(
SELECT CAST(N'<x>' + REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(teststring,N' - ',N' '),N'&',N'&'),N'<',N'<'),N'>',N'>'),N' ',N'</x><x>') + N'</x>' AS XML) testXML
FROM #input
)
SELECT testXML.value('/x[1]','int') AS Number
,testXML.value('/x[2]','nvarchar(max)') AS Part1
,testXML.value('/x[3]','nvarchar(max)') AS Part2
,testXML.value('/x[4]','nvarchar(max)') AS Part3
FROM Splitted
The result
Number Part1 Part2 Part3
27364 John Smith NULL
27364 John Andrew Smith

Answer 2

SQL Server 2016 has a new built-in function called STRING_SPLIT()
Assuming creating built-in functions, but CLR functions are not allowed:
CREATE FUNCTION dbo.WORD_SPLIT
(
#String AS nvarchar(4000)
)
RETURNS TABLE
AS
RETURN
(
WITH Spaces AS
(
SELECT Spaced.[value], ROW_NUMBER() OVER (PARTITION BY 1 ORDER BY (SELECT 1)) AS ordinal
FROM STRING_SPLIT(#String, ' ') AS Spaced
)
, Tabs AS
(
SELECT Tabbed.[value], ROW_NUMBER() OVER (PARTITION BY 1 ORDER BY s.ordinal, (SELECT 1)) AS ordinal
FROM Spaces AS s
CROSS APPLY STRING_SPLIT(s.[value], ' ') AS Tabbed
)
, NewLines1 AS
(
SELECT NewLined1.[value], ROW_NUMBER() OVER (PARTITION BY 1 ORDER BY t.ordinal, (SELECT 1)) AS ordinal
FROM Tabs AS t
CROSS APPLY STRING_SPLIT(t.[value], CHAR(13)) AS NewLined1
)
, NewLines2 AS
(
SELECT NewLined2.[value], ROW_NUMBER() OVER (PARTITION BY 1 ORDER BY nl1.ordinal, (SELECT 1)) AS ordinal
FROM NewLines1 AS nl1
CROSS APPLY STRING_SPLIT(nl1.[value], CHAR(10)) AS NewLined2
)
SELECT LTRIM(RTRIM(nl2.[value])) AS [value], ROW_NUMBER() OVER (PARTITION BY 1 ORDER BY nl2.ordinal, (SELECT 1)) AS ordinal
FROM NewLines2 AS nl2
WHERE LTRIM(RTRIM(nl2.[value])) <> ''
)
GO
Usage:
-- Not Normailized
SELECT i.*, split.[value], split.[ordinal]
FROM #input AS i
CROSS APPLY dbo.WORD_SPLIT(i.teststring) AS split
-- Normalized
;WITH Splitted AS
(
SELECT split.[value], split.[ordinal]
FROM #input AS i
CROSS APPLY dbo.WORD_SPLIT(i.teststring) AS split
)
SELECT *
FROM (SELECT [value], 'part' + CONVERT(nvarchar(20), [ordinal]) AS [parts] FROM Splitted) AS s
PIVOT (MAX([value]) FOR [parts] IN ([part1], [part2], [part3], [part4])
Or assuming that, per-security, you are not allowed to make schema changes:
WITH Splitting AS
(
SELECT teststring AS [value]
FROM #input
)
WITH Spaces AS
(
SELECT Spaced.[value], ROW_NUMBER() OVER (PARTITION BY 1 ORDER BY (SELECT 1)) AS ordinal
FROM Splitting AS sp
CROSS APPLY STRING_SPLIT(sp.[value], ' ') AS Spaced
)
, Tabs AS
(
SELECT Tabbed.[value], ROW_NUMBER() OVER (PARTITION BY 1 ORDER BY s.ordinal, (SELECT 1)) AS ordinal
FROM Spaces AS s
CROSS APPLY STRING_SPLIT(s.[value], ' ') AS Tabbed
)
, NewLines1 AS
(
SELECT NewLined1.[value], ROW_NUMBER() OVER (PARTITION BY 1 ORDER BY t.ordinal, (SELECT 1)) AS ordinal
FROM Tabs AS t
CROSS APPLY STRING_SPLIT(t.[value], CHAR(13)) AS NewLined1
)
, NewLines2 AS
(
SELECT NewLined2.[value], ROW_NUMBER() OVER (PARTITION BY 1 ORDER BY nl1.ordinal, (SELECT 1)) AS ordinal
FROM NewLines1 AS nl1
CROSS APPLY STRING_SPLIT(nl1.[value], CHAR(10)) AS NewLined2
)
, Splitted AS
(
SELECT LTRIM(RTRIM(nl2.[value])) AS [teststring], ROW_NUMBER() OVER (PARTITION BY 1 ORDER BY nl2.ordinal, (SELECT 1)) AS ordinal
FROM NewLines2 AS nl2
WHERE LTRIM(RTRIM(nl2.[value])) <> ''
)
SELECT *
FROM (SELECT [value], 'part' + CONVERT(nvarchar(20), [ordinal]) AS [parts] FROM Splitted) AS s
PIVOT (MAX([value]) FOR [parts] IN ([part1], [part2], [part3], [part4])
Hopefully helpful!