Generate xml from ms sql with head and item tables - sql-server

Question

I'd like to generate an xml from MS SQL with a structure like this (invoice head info, then invoice items info):
<?xml version="1.0" encoding="ISO8859-2"?>
<Data HD="1" View="InvoiceGen">
<Row Table="InvoiceHead">
<InvoiceNumber>630506</InvoiceNumber>
<CustomerId>1432</CustomerId>
</Row>
<Row Table="InvoiceItem">
<ItemNumber>B52</ItemNumber>
<Price>320</Price>
<Tax>30</Tax>
</Row>
<Row>
<ItemNumber>B53</ItemNumber>
<Price>330</Price>
<Tax>32</Tax>
</Row>
<Row Table="InvoiceHead">
<InvoiceNumber>630626</InvoiceNumber>
<CustomerId>1556</CustomerId>
</Row>
<Row Table="InvoiceItem">
<ItemNumber>B5</ItemNumber>
<Price>500</Price>
<Tax>55</Tax>
</Row>
<Row>
<ItemNumber>B5</ItemNumber>
<Price>200</Price>
<Tax>20</Tax>
</Row>
<Row>
<ItemNumber>B18</ItemNumber>
<Price>180</Price>
<Tax>16</Tax>
</Row>
</Data>
i have an invoice head table, and an invoice item table (InvoiceNumer makes the connection between the two):
InvoiceHead (InvoiceNumber,CustomerId)
InvoiceItem (InvoiceNumber,ItemNumber,Price,Tax)
I have already created a table with the combined data, with the same structure as in the desired xml:
InvoiceGen(InvoiceNumber,CustomerId,ItemNumber,Price,Tax)
In this table, after a head row there are all the rows with the item information connected to the invoice head. (Just like in the xml)
The contet of this InvoiceGen table is:
InvoiceNumber CustomerId ItemNumber Price Tax
630506 1432 null null null
630506 1432 B52 320 30
630506 1432 B53 330 32
630626 1556 null null null
630626 1556 B5 500 55
630626 1556 B6 200 20
630626 1556 B18 180 16
I'm not sure if this table can help me, but it looked like a good idea.
Can anyone help me to create an xml like the above?
Thank you!

Answer 1

This basically gets you to what you want. Note, however, that 'B18' is sorted before 'B5' and 'B6' because your values are varchars. With a varchar the value '1' and a lower value than '5', and so '18' as a "lower" value than '5':
WITH VTE AS(
SELECT *
FROM (VALUES (630506,1432,NULL,NULL,NULL),
(630506,1432,'B52',320,30),
(630506,1432,'B53',330,32),
(630626,1556,NULL,NULL,NULL),
(630626,1556,'B5',500 ,55),
(630626,1556,'B6',200,20),
(630626,1556,'B18',180,16)) V(InvoiceNumber,CustomerID,ItemNumber,Price,Tax))
SELECT 1 aS [#HD],
'InvoiceGen' AS [#View],
(SELECT CASE WHEN ItemNumber IS NULL THEN 'InvoiceHead' ELSE 'InvoiceItem' END AS [#Table],
CASE WHEN ItemNumber IS NULL THEN InvoiceNumber END AS InvoiceNumber,
CASE WHEN ItemNumber IS NULL THEN CustomerID END AS CustomerID,
ItemNumber,
Price,
Tax
FROM VTE V
ORDER BY V.InvoiceNumber,
V.CustomerID,
CASE WHEN V.ItemNumber IS NULL THEN 0 ELSE 1 END,
V.ItemNumber
FOR XML PATH('Row'),TYPE)
FOR XML PATH('Data');