Extract all the XML entry key values as rows using SQL - sql

Question

I'm trying to extract the key values (1,2,3) from a single row in a table, but I'm only able to extract a single row at a time using what I know:
cast([attributes] as XML).value('(//Map/entry[#key="catalogItem"]/value/Map/entry/#key)[1]','VARCHAR(20)')
Depending on what number I put in the [x] I get that entry.
I tried removing the [x] and got the error: XQuery [value()]: 'value()' requires a singleton (or empty sequence), found operand of type 'xdt:untypedAtomic *'
<Map>
<entry key="catalogItem">
<value>
<Map>
<entry key="1" value="x"/>
<entry key="2" value="y"/>
<entry key="3" value="z"/>
I want the results to be a single column
1
2
3

Answer 1

Please try the following solution.
A combination of XQuery methods .nodes() and .value() gives what you need.
SQL
-- DDL and sample data population, start
DECLARE #tbl TABLE (id INT IDENTITY PRIMARY KEY, XMLColumn XML);
INSERT INTO #tbl (XMLColumn) VALUES
(N'<Map>
<entry key="catalogItem">
<value>
<Map>
<entry key="1" value="x"/>
<entry key="2" value="y"/>
<entry key="3" value="z"/>
</Map>
</value>
</entry>
</Map>');
-- DDL and sample data population, end
SELECT t.*
, c.value('#key', 'INT') AS [key]
FROM #tbl AS t
CROSS APPLY XMLColumn.nodes('/Map/entry/value/Map/entry') AS t1(c);
Output
id
key
1
1
1
2
1
3