tsql code to sync two xml documents - sql

Question

xml 1
<Team>
<Players>
<Player id="1" timestamp="11/03/2012 08:10:12">30</Player>
<Player id="2" timestamp="11/02/2012 09:11:12">40</Player>
<Players>
</Team>
xml 2
<Team>
<Players>
<Player id="1" timestamp="11/02/2012 09:10:12">10</Player>
<Player id="2" timestamp="11/03/2012 10:11:12">20</Player>
<Player id="3" timestamp="11/03/2012 13:00:00">50</Player>
<Players>
</Team>
OUTPUT when we merge the above two XMLs based on timestamp element:
<Team>
<Players>
<Player id="1" timestamp="11/02/2012 09:10:12">30</Player>
<Player id="2" timestamp="11/03/2012 10:11:12">20</Player>
<Player id="3" timestamp="11/03/2012 13:00:00">50</Player>
<Players>
</Team>
Could anyone please help me with T-SQL code to do this in SQL Server 2005/2008

Answer 1

Using this approach with two nested CTE's, you can get close - but not all the way:
DECLARE #XML1 XML = '<Team>
<Players>
<Player id="1" timestamp="11/03/2012 08:10:12">30</Player>
<Player id="2" timestamp="11/02/2012 09:11:12">40</Player>
</Players>
</Team>'
DECLARE #XML2 XML = '<Team>
<Players>
<Player id="1" timestamp="11/02/2012 09:10:12">10</Player>
<Player id="2" timestamp="11/03/2012 10:11:12">20</Player>
<Player id="3" timestamp="11/03/2012 13:00:00">50</Player>
</Players>
</Team>'
-- extract the ID, Timestamp and node values from both XML variables
;WITH CTE AS
(
SELECT
ID = P1.value('#id', 'int'),
TS = P1.value('#timestamp', 'datetime2'),
NodeValue = P1.value('(.)[1]', 'int')
FROM #XML1.nodes('/Team/Players/Player') AS XTbl1(P1)
UNION
SELECT
ID = P2.value('#id', 'int'),
TS = P2.value('#timestamp', 'datetime2'),
NodeValue = P2.value('(.)[1]', 'int')
FROM #XML2.nodes('/Team/Players/Player') AS XTbl2(P2)
),
-- partition and sequentially number the result, so that the newest
-- (most recent) item can be extracted
CTE2 AS
(
SELECT ID, TS, NodeValue,
RowNum = ROW_NUMBER() OVER(PARTITION BY ID ORDER BY TS DESC)
FROM CTE
)
SELECT
ID AS '#id',
TS AS '#timestamp',
NodeValue AS 'text()'
FROM CTE2
WHERE RowNum = 1
FOR XML PATH('Player'), ROOT('Players')
Results in output like this:
<Players>
<Player id="1" timestamp="2012-11-03T08:10:12">30</Player>
<Player id="2" timestamp="2012-11-03T10:11:12">20</Player>
<Player id="3" timestamp="2012-11-03T13:00:00">50</Player>
</Players>