Looping thru xml then updating xml variable in SQL - sql

Question

My xml looks like the ff:
<root>
<TemplateQuestion>
<Row rfqID="1" rftID="1" questionDesc="Question 1" responseType="1" rfqDisplayOrder="1" deletedBit="0" />
<Row rfqID="2" rftID="1" questionDesc="Question 2" responseType="2" rfqDisplayOrder="2" deletedBit="0" />
<Row rfqID="3" rftID="1" questionDesc="Question 3" responseType="3" rfqDisplayOrder="3" deletedBit="0" />
</TemplateQuestion>
</root>
Now my goal is to make the rfqID to have the letter "q" before it. So the results should be like the ff:
<root>
<TemplateQuestion>
<Row rfqID="q1" rftID="1" questionDesc="Question 1" responseType="1" rfqDisplayOrder="1" deletedBit="0" />
<Row rfqID="q2" rftID="1" questionDesc="Question 2" responseType="2" rfqDisplayOrder="2" deletedBit="0" />
<Row rfqID="q3" rftID="1" questionDesc="Question 3" responseType="3" rfqDisplayOrder="3" deletedBit="0" />
</TemplateQuestion>
</root>
I am achieving that by doing this:
declare #xml XML
set #xml = (select dbo.udfGetXMLVal(1))
declare #nodeCount int
declare #i int
declare #qid nvarchar(20)
set #i = 1
select #nodeCount = #xml.value('count(/root/TemplateQuestion/Row/#rfqID)','int')
while(#i <= #nodeCount)
begin
select #qid = x.value('#rfqID[1]', 'VARCHAR(20)')
from #xml.nodes('/root/TemplateQuestion/Row[position()=sql:variable("#i")]') e(x)
set #qid = 'q' + #qid
select #qid
Set #xml.modify('replace value of (/root/TemplateQuestion/Row/#rfqID)[1] with sql:variable("#qid")')
set #i = #i + 1
end
Im having problems with this line:
Set #xml.modify('replace value of (/root/TemplateQuestion/Row/#rfqID)[1] with sql:variable("#qid")')
How can I replace the [1] to the variable #i? I get some error with string literals when I try to use sql:variable.
Any help you could provide would be greatly appreciated. Thank you

Answer 1

"How can I replace the [1] to the variable #i? I get some error with string literals when I try to use sql:variable"
You can do it like this (tested and works in SQL Server 2008R2) :
Set #xml.modify('
replace value of ((/root/TemplateQuestion/Row/#rfqID)[sql:variable("#i")] )[1]
with sql:variable("#qid")
')

Answer 2

Quick and dirty :-)
SELECT CAST(REPLACE(CAST(#x AS VARCHAR(MAX)),' rftID="',' rftID="q') AS XML);
And here's a clean approach:
DECLARE #x XML='<root>
<TemplateQuestion>
<Row rfqID="1" rftID="1" questionDesc="Question 1" responseType="1" rfqDisplayOrder="1" deletedBit="0" />
<Row rfqID="2" rftID="1" questionDesc="Question 2" responseType="2" rfqDisplayOrder="2" deletedBit="0" />
<Row rfqID="3" rftID="1" questionDesc="Question 3" responseType="3" rfqDisplayOrder="3" deletedBit="0" />
</TemplateQuestion>
</root>';
SELECT
(
SELECT 'q' + R.value('#rfqID','varchar(max)') AS [#rfqID]
,R.value('#rftID','int') AS [#rftID]
,R.value('#questionDesc','varchar(max)') AS [#questionDesc]
--other attributes similar
FROM #x.nodes('/root/TemplateQuestion/Row') AS A(R)
FOR XML PATH('Row'),ROOT('TemplateQuestion'),TYPE
)
FOR XML PATH('root');