SQL Split function - sql

Question

I'm looking for a way to do this ...
SELECT FirstName, LastName, Split(AddressBlock, ' ', 1), Split(AddressBlock, ' ', 2), PostCode
FROM Contacts
The arguments I want to pass are ...
The address
The separator (current situation requires 2 spaces but this might be a comma or a space followed by a comma) or something else (it varies).
The address part I want to return (i don't always need all parts of the split result).
I seem to be able to find a few examples of splitting functions about the internet but they return a table containing the entire set of split parts.
My SQL skills aren't that great so I need the answer to be ultra simple.
I'm always working with nvarchar data and the function needs to be reusable.

Answer 1

If you want a user-defined function to do this, this should work. Not that pretty, but...
CREATE FUNCTION dbo.SplitStringPart (
#input nvarchar(MAX),
#separator nvarchar(10),
#index int
) RETURNS nvarchar(MAX)
BEGIN
DECLARE #counter int,
#position int,
#oldposition int,
#separatorlength int,
#result nvarchar(MAX)
SET #separatorlength = DATALENGTH(#separator) / 2
IF #separatorlength = 0 RETURN NULL
SET #result = NULL
SET #counter = 1
SET #position = -2
WHILE (#counter <= #index)
BEGIN
SET #oldposition = #position
SET #position = CHARINDEX(#separator, #input, #position + 1)
IF #position = 0 AND #counter < #index
BEGIN
SET #oldposition = 0
BREAK
END
SET #counter = #counter + 1
END
IF #oldposition = 0 AND #position = 0
RETURN NULL
ELSE IF #oldposition < 0
BEGIN
IF #position = 0 AND #index = 1
SET #result = #input
ELSE
SET #result = SUBSTRING(#input, 0, #position)
END
ELSE IF #position <= 0
SET #result = SUBSTRING(#input, #oldposition + #separatorlength, LEN(#input) - #oldposition - #separatorlength)
ELSE
SET #result = SUBSTRING(#input, #oldposition + #separatorlength, #position - #oldposition - #separatorlength)
RETURN #result
END
GO

Answer 2

It's not pretty, but add this to you SQL statement and it should work:
CASE
WHEN charindex(' ', substring(AddressBlock, (charindex(' ', AddressBlock) + 1), len(AddressBlock))) > 0 THEN substring(AddressBlock, (charindex(' ', AddressBlock) + 1), charindex(' ', substring(AddressBlock, (charindex(' ', AddressBlock) + 1), len(AddressBlock))) - 1)
ELSE substring(AddressBlock, (charindex(' ', AddressBlock) + 1), len(AddressBlock))
END AS 'Address 1',
CASE WHEN charindex(' ', substring(AddressBlock, (charindex(' ', AddressBlock) + 1), len(AddressBlock))) > 0 THEN substring(AddressBlock, charindex(' ', AddressBlock) + charindex(' ', substring(AddressBlock, (charindex(' ', AddressBlock) + 1), len(AddressBlock))) + 1, Len(AddressBlock))
ELSE ''
END AS 'Address 2'

Answer 3

Here is my version of the answer. This is MUCH faster and robust. No need to fuss around with substrings, charindex, etc.
CREATE FUNCTION [dbo].[SplitArray]
(
#RowToSplit nvarchar(MAX),
#Delimeter nvarchar(MAX)
)
RETURNS #RtnValue table (ID bigint IDENTITY, Data nvarchar(MAX))
AS
BEGIN
DECLARE #xml xml
SET #xml = '<field>' + REPLACE(#RowToSplit, #Delimeter, '</field><field>') + '</field>'
INSERT INTO #RtnValue(data)
SELECT tbl.c.value('.','nvarchar(max)')
FROM #xml.nodes('/field') tbl(c)
RETURN
END
You would simply use the resultant split values in a table, like this:
SELECT Data FROM dbo.SplitArray('this is great',' ')
This will return:
Data
============
this
is
great