Union in SQL while creating XML file

Question

I got some problem with my SQL query which create a XML file. I want to do UNION it this query but it doesn\'t work.

(SELECT 1 AS \"ns0:kindOfIt         


        

Answer 1

You might be interested in this:

Please compare the following

The word "test" occurs in both lists. UNION will do a DISTINCT implicitly, so "test" appears only once.

SELECT * 
FROM (VALUES('this'),('is'),('a'),('test')) AS tbl(Words)
UNION
SELECT * 
FROM (VALUES('and'),('another'),('test')) AS tbl(Words);

The same with UNION ALL will let the "test" appear twice

SELECT * 
FROM (VALUES('this'),('is'),('a'),('test')) AS tbl(Words)
UNION ALL
SELECT * 
FROM (VALUES('and'),('another'),('test')) AS tbl(Words);

You can put your UNION SELECT into a surrounding SELECT (either UNION or UNION ALL and set the FOR XML PATH for the whole result-set

The namespace is created repeatedly, not wrong, but annoying (see this: https://stackoverflow.com/a/35648751/5089204 and the linked Connect-Article)

WITH XMLNAMESPACES(DEFAULT 'Dummy') 
SELECT *
FROM
(
    SELECT * 
    FROM (VALUES('this'),('is'),('a'),('test')) AS tbl(Words)
    UNION
    SELECT * 
    FROM (VALUES('and'),('another'),('test')) AS tbl(Words)
) AS MetaTable
FOR XML Path(''),ROOT('UNION_TEST');

This will bring back both lists, each in its own XML tag, also repeated namespace (see before)

WITH XMLNAMESPACES(DEFAULT 'Dummy') 
SELECT
 (
    SELECT * 
    FROM (VALUES('this'),('is'),('a'),('test')) AS tbl(Words)
    FOR XML PATH(''),ROOT('FirstBlock'),TYPE
 )
,(
    SELECT * 
    FROM (VALUES('and'),('another'),('test')) AS tbl(Words)
    FOR XML PATH(''),ROOT('FirstBlock'),TYPE
 )
FOR XML Path(''),ROOT('UNION_TEST');

And finally you can use this too (either with ALL or not):

WITH XMLNAMESPACES(DEFAULT 'Dummy') 
SELECT * 
FROM (VALUES('this'),('is'),('a'),('test')) AS tbl(Words)
UNION ALL
SELECT * 
FROM (VALUES('and'),('another'),('test')) AS tbl(Words)
FOR XML PATH(''),ROOT('UNION_TEST');