See if this works?CREATE TABLE #tmp (id INT, DebtorNumber INT, InvoiceNumber INT, VALUE INT, DebtorValue INT);
INSERT INTO #tmp VALUES
(1,12345,1000,999,15000),
(2,12345,1001,593,15000),
(3,12345,1002,19,15000),
(4,98023,500,223,8000)
SELECT
debtornumber AS dimension,
debtorvalue,
(
SELECT a.id,a.invoicenumber, a.value
FROM #tmp a
WHERE a.DebtorNumber = b.debtornumber
FOR XML PATH('detail'),TYPE
) AS details
FROM
#tmp b
FOR XML PATH(''), ROOT('summary');
DROP TABLE #tmp;