Break up Text string to use in Join in SQL Server 2008 - sql

Question

Good Day,
I am busy creating a tax document for discount entries out of our debtors transaction table. One of the requirements is that the discount amount must indicate to which transaction it relates. This information is available but I do not know how to use it because it is in a single delimited text field. The table looks as follows.
╔═════════╦════════════╦══════╦════════╦═══════════╦══════════════════════════════════════════╗
║ AutoIdx ║ TxDate ║ Id ║ Amount ║ Reference ║ cAllocs ║
╠═════════╬════════════╬══════╬════════╬═══════════╬══════════════════════════════════════════╣
║ 1 ║ 30-07-2014 ║ OInv ║ 100 ║ IN543 ║ I=4;A=99;D=20140730|I=3;A=1;D=20140730 ║
║ 2 ║ 30-07-2014 ║ OInv ║ 200 ║ IN544 ║ I=4;A=198;D=20140730|I=3;A=2;D=20140730 ║
║ 3 ║ 30-07-2014 ║ DS ║ 3 ║ DISC ║ I=1;A=1;D=20140730|I=2;A=2;D=20140730 ║
║ 4 ║ 30-07-2014 ║ Pmnt ║ 297 ║ PMNT ║ I=1;A=99;D=20140730|I=2;A=198;D=20140730 ║
╚═════════╩════════════╩══════╩════════╩═══════════╩══════════════════════════════════════════╝
In the column cAllocs you have the information that links the lines with each other. It has three indicators
I - the line in this table that it links to
A - the amount of the link transaction
D - the date of the transaction
It can have only one set of these or many sets delimited with a pipe character.
I want to end up with a table that has only the entries with Id "DS" but giving me the reference column value of the lines it links to in a single column (they can be delimited by comma)
So from the above table I would like to get this result.
╔════════════╦════╦════════╦═══════════╦═════════════╗
║ TxDate ║ Id ║ Amount ║ Reference ║ MatchedTo ║
╠════════════╬════╬════════╬═══════════╬═════════════╣
║ 30-07-2014 ║ DS ║ 3 ║ DISC ║ IN543,IN544 ║
╚════════════╩════╩════════╩═══════════╩═════════════╝
Thanks for any replies

Answer 1

You can create a function that handles string manipulation and retrieves the data at the same time. Try this one below:
CREATE FUNCTION [dbo].[GetReferenceFromCAllocs](#cAllocs VARCHAR(MAX))RETURNS VARCHAR(MAX)AS
BEGIN
DECLARE #val AS VARCHAR(MAX)
DECLARE #ch AS CHAR(1)
DECLARE #result AS VARCHAR(MAX)
DECLARE #returnValue AS VARCHAR(MAX)
SET #val = #cAllocs
SET #result = ''
SET #returnValue = ''
DECLARE #idx INT
SET #idx = 1
WHILE #idx < LEN(#val)
BEGIN
SET #ch = SUBSTRING(#val,#idx,1)
IF(#ch = 'I')
BEGIN
DECLARE #idx2 INT
DECLARE #temp VARCHAR(5)
SET #temp = #ch
SET #idx2 = #idx + 1
SET #ch = SUBSTRING(#val,#idx2,1)
WHILE #ch <> ';'
BEGIN
SET #temp = #temp + #ch
SET #idx2 = #idx2 + 1
SET #ch = SUBSTRING(#val,#idx2,1)
END
SET #idx = #idx2
SET #result = #result + #temp + ';'
END
ELSE
SET #idx = #idx + 1
END
SET #idx = 1
WHILE #idx < LEN(#result)
BEGIN
SET #ch = SUBSTRING(#val,#idx,1)
IF(#ch = '=')
BEGIN
SET #temp = ''
SET #idx2 = #idx + 1
SET #ch = SUBSTRING(#result,#idx2,1)
WHILE #ch <> ';'
BEGIN
SET #temp = #temp + #ch
SET #idx2 = #idx2 + 1
SET #ch = SUBSTRING(#result,#idx2,1)
END
SET #idx = #idx2
DECLARE #tempValue AS VARCHAR(10)
SET #tempValue = ''
SELECT #tempValue = Reference FROM YOUR_TABLE
WHERE AutoIdx = #temp
SET #returnValue = #returnValue + #tempValue + ','
END
ELSE
SET #idx = #idx + 1
END
RETURN SUBSTRING(#returnValue,1, LEN(#returnValue)-1)
END
--EDIT: The function above will get all data with I as it's prefix:
E.g:
Passed Value: I=4;A=99;D=20140730|I=3;A=1;D=20140730
Result Value: I=4;I=3;
After that, it queries the corresponding Reference with AutoIdx 4 and 3; then returns it in a format as specified in your question.
Then, run this sql:
SELECT
yt.TxDate,
yt.Id,
yt.Amount,
yt.Reference,
dbo.GetReferenceFromCAllocs(yt.cAllocs) AS MatchedTo
FROM YOUR_TABLE yt
WHERE yt.Id = 'DS'
Hope this would work. Just adjust the SQL codes to optimize it. I'm in a hurry so I used safest values (such as VARCHAR(MAX)).