Manipulate XMLNamespaces - sql-server

Question

I have the following output from SQL using FOR XML clause:
<q17:DestinationSection xmlns:q17="http://ITrack.Transmission/2011/02/25/Objects">
<q17:DestinationCode>1</q17:DestinationCode>
<q17:DestinationName>Strada Rampei 9, Iasi</q17:DestinationName>
<q17:DestinationAddress1>Strada Rampei 9, Iasi</q17:DestinationAddress1>
<q17:DestinationAddress2>
xsi:nil="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
</q17:DestinationAddress2>
</q17:DestinationSection>
The DestinationSection is the main root for this block of data. Is there any possibility to do some workaround and to have something like below in the <q17:DestinationAddress2></q17:DestinationAddress2> tag?
<q17:DestinationAddress2 xsi:nil="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"</q17:DestinationAddress2>
I have tried something but I get an error that says that I need to declare the namespace but I really don't know where to "introduce" that definition.
My SQL statement
DECLARE #XMLFINAL VARCHAR(MAX)
SET #XMLFINAL=''
DECLARE #XMLFINAL2 VARCHAR(MAX)
SET #XMLFINAL2=''
DECLARE #NUMBER NVARCHAR(100)
DECLARE #NUMBER2 NVARCHAR(100)
DECLARE #XML VARCHAR(MAX)
DECLARE #XML2 VARCHAR(MAX)
DECLARE Rec CURSOR FAST_FORWARD FOR
SELECT GID FROM PurchaseDocumentsHeader
OPEN Rec
FETCH NEXT FROM Rec INTO #NUMBER2
WHILE ##FETCH_STATUS = 0
BEGIN
SET #XML2=''
;WITH XMLNAMESPACES ('http://ITrack.Transmission/2011/02/25/Objects' as q17)
SELECT #XML2= (
SELECT
DestCode AS 'q17:DestinationCode', DestDescr 'q17:DestinationName', DestAddr AS 'q17:DestinationAddress1', DestAddr2 AS 'q17:DestinationAddress2',
DestZIP AS 'q17:DestinationZIP'
FROM PurchaseDocumentsHeader WHERE GID=#NUMBER2
FOR XML RAW('q17:DestinationSection'),ELEMENTS
)
FETCH NEXT FROM Rec INTO #NUMBER2
SET #XMLFINAL2=#XMLFINAL2+#XML2
END
CLOSE Rec DEALLOCATE Rec
EDIT
Please find below my DDL. It's a view used to extract the data from an official table.
CREATE VIEW [dbo].[PurchaseDocumentsHeader]
AS
SELECT esd.GID, esd.ADRegistrationDate, esgo.Code AS DestCode, esgo.Description AS DestDescr, esgo.Address1 AS DestAddr, esgo.fCityCode AS DestCity,
esgp.TaxRegistrationNumber AS DestZIP, 'xsi:nil="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"' AS DestAddr2, esgo.Description AS DestRomanized,
esgo.Address1 AS DestAddress1Romanized,
'xsi:nil="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"' AS DestAddress2Romanized, esgp.TaxRegistrationNumber AS DestZIPRom,
esgo.fCityCode AS DestCityRomanized, esgo.fCountryCode AS DestCountry, cast('DestinationGLN xsi:nil="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"/>' AS XML) AS DestGLN,
'xsi:nil="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"' AS DestCoord
FROM ESFIDocumentTrade esd
LEFT JOIN ESGOSites esgo on esd.fDeliverySiteGID=esgo.GID
LEFT JOIN ESFITradeAccount esc on esd.fTradeAccountGID=esc.GID
LEFT JOIN ESGOPerson esgp on esc.fPersonCodeGID=esgo.GID
LEFT JOIN ESFIDocumentType est on esd.fADDocumentTypeGID=est.GID
WHERE esd.fTransitionStepCode='APPROVED' AND est.Code='CVR'
AND YEAR(esd.ADRegistrationDate)=YEAR(GETDATE())
AND MONTH(esd.ADRegistrationDate)=MONTH(GETDATE())
AND DAY(esd.ADRegistrationDate)=DAY(GETDATE())
GO
Later edit
CREATE TABLE DocPurcharseHeader
(
ADRegistrationDate date,
Code NVARCHAR(4000),
Description NVARCHAR(4000),
Address1 NVARCHAR (4000),
Address2 NVARCHAR (4000),
City NVARCHAR (4000),
ZIPCode NVARCHAR(4000)
)
INSERT INTO DocPurcharseHeader (ADRegistrationDate, Code, Description, Address1, Address2, City, ZIPCode)
VALUES('2017-10-16', '01', 'MyPOS', 'MyPOSAddress1', 'MyPOSAddress2', 'BUCHAREST', '123456')
2nd Later edit
;WITH XMLNAMESPACES ('http://ITrack.Transmission/2011/02/25/Objects' as q17)
SELECT #XMLSalesOrders=(
SELECT DestCode AS [q17:DestinationCode]
,DestDescr AS [q17:DestinationName]
,DestAddr AS [q17:DestinationAddress1]
,DestAddr2 AS [q17:DestinationAddress2]
FROM PurchaseDocumentsHeader
FOR XML PATH('q17:DestinationSection'),ELEMENTS XSINIL,ROOT('q17:DestinationSections'))
This code above is generating the below output, without XSINL directive:
<q17:DestinationSections xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:q17="http://ITrack.Transmission/2011/02/25/Objects">
<q17:DestinationSection>
<q17:DestinationCode>1</q17:DestinationCode>
<q17:DestinationName>Strada Rampei 9, Iasi</q17:DestinationName>
<q17:DestinationAddress1>Strada Rampei 9, Iasi</q17:DestinationAddress1>
<q17:DestinationAddress2/>
</q17:DestinationSection>
<q17:DestinationSection>

Answer 1

you are trying to out-trick the very mighty XML engine.
As stated in your other question:
Never do this in a CURSOR! They are bad and evil, coming directly of the hell of procedural thinking and were invented by the devil of spaghetti code...
Try it like this:
I use your table DDL an insert some data. The second row will have a NULL in address2. Normally XML will simply omit NULL values. A not existing node is read as a NULL value. But you can force NULLs to be introduced as xsi.nil="true" with ELEMENTS XSINIL:
CREATE TABLE DocPurcharseHeader
(
ADRegistrationDate date,
Code NVARCHAR(4000),
Description NVARCHAR(4000),
Address1 NVARCHAR (4000),
Address2 NVARCHAR (4000),
City NVARCHAR (4000),
ZIPCode NVARCHAR(4000)
);
INSERT INTO DocPurcharseHeader (ADRegistrationDate, Code, Description, Address1, Address2, City, ZIPCode)
VALUES('2017-10-16', '01', 'MyPOS', 'MyPOSAddress1', 'MyPOSAddress2', 'BUCHAREST', '123456')
,('2017-10-16', '01', 'MyPOS', 'MyPOSAddress1', NULL, 'BUCHAREST', '123456');
WITH XMLNAMESPACES('http://ITrack.Transmission/2011/02/25/Objects' AS q17)
SELECT Code AS [q17:DestinationCode]
,Description AS [q17:DestinationName]
,Address1 AS [q17:DestinationAddress1]
,Address2 AS [q17:DestinationAddress2]
FROM DocPurcharseHeader
FOR XML PATH('q17:DestinationSection'),ELEMENTS XSINIL,ROOT('q17:DestinationSections');
The result
<q17:DestinationSections xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:q17="http://ITrack.Transmission/2011/02/25/Objects">
<q17:DestinationSection>
<q17:DestinationCode>01</q17:DestinationCode>
<q17:DestinationName>MyPOS</q17:DestinationName>
<q17:DestinationAddress1>MyPOSAddress1</q17:DestinationAddress1>
<q17:DestinationAddress2>MyPOSAddress2</q17:DestinationAddress2>
</q17:DestinationSection>
<q17:DestinationSection>
<q17:DestinationCode>01</q17:DestinationCode>
<q17:DestinationName>MyPOS</q17:DestinationName>
<q17:DestinationAddress1>MyPOSAddress1</q17:DestinationAddress1>
<q17:DestinationAddress2 xsi:nil="true" />
</q17:DestinationSection>
</q17:DestinationSections>
UPDATE: About NULL values:
Try this
DECLARE #DummyTable TABLE(SomeDescription VARCHAR(500), SomeValue VARCHAR(100));
INSERT INTO #DummyTable VALUES('A real NULL value',NULL)
,('An empty string','')
,('A blank string',' ')
,('Some Text','blah blah');
WITH XMLNAMESPACES('SomeURL' AS q17)
SELECT SomeDescription AS [q17:Description]
,SomeValue AS [q17:Value]
FROM #DummyTable
FOR XML PATH('q17:row'),ELEMENTS XSINIL,ROOT('root');
To get this
<root xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:q17="SomeURL">
<q17:row>
<q17:Description>A real NULL value</q17:Description>
<q17:Value xsi:nil="true" />
</q17:row>
<q17:row>
<q17:Description>An empty string</q17:Description>
<q17:Value></q17:Value>
</q17:row>
<q17:row>
<q17:Description>A blank string</q17:Description>
<q17:Value> </q17:Value>
</q17:row>
<q17:row>
<q17:Description>Some Text</q17:Description>
<q17:Value>blah blah</q17:Value>
</q17:row>
</root>
You can see, that the real NULL is encoded as xsi:nil="true", while the empty string is shown as <q17:Value></q17:Value> (which is exactly the same as <q17:Value />).
Check this answer for some examples about NULL and empty. Check this answer to understand more about text()