SQL Server "FOR XML" output from queries joining two tables - sql

Question

I'm new to the "FOR XML" feature in SQL Server. I am using SQL Server 2012.
I have two tables, Word and Word_Expansion.
Sample data:
table [Word]:
WordOID Word
------- ----
1 PIPE
2 WIRE
table [Word_Expansion]:
WEOID fk_WordOID Word_Expansion
----- ---------- --------------
1 2 COAX
2 2 SPEAKER CABLE
3 1 CONDUIT
Now, I would like to produce XML something like:
<expansion>
<sub>WIRE</sub>
<sub>SPEAKER CABLE</sub>
</expansion>
<expansion>
<sub>PIPE</sub>
<sub>CONDUIT</sub>
</expansion>
I have come close with various efforts at crafting XML FOR statements, but I just can't seem to grasp what it is that I need to do to get these two tables mashed into the right XML output. I'll be digging further into XML FOR syntax, but if you have a moment and know this well...
Does anyone have any pointers as to what I should try?

Answer 1

This should do the trick for you:
SQL:
SELECT Word Sub,
(
SELECT Word_Expansion AS Sub
FROM Word_Expansion WE
WHERE WE.fk_WordOID = W.WordOID
FOR XML PATH(''), type
)
FROM Word W
FOR XML PATH ('Expansion')
XML Output:
<Expansion>
<Sub>Pipe</Sub>
<Sub>CONDUIT</Sub>
</Expansion>
<Expansion>
<Sub>Wire</Sub>
<Sub>COAX</Sub>
<Sub>SPEAKER CABLE</Sub>
</Expansion>
Although i'm not sure why you want Word.Word to be classified as "Sub"?
Shouldn't this instead be the parent of Word_Expansion (which should be sub?)
EDIT: I found this link quite useful when looking into FOR XML and nested queries Nested FOR XML

Answer 2

Here is mine... I upvoted the first post because his was fastest, but it does it a little different so I figured it couldn't hurt to add mine...
With groupedWords
As
(
Select WordOID,
Word
From Word
Union
Select fk_WordOID, Word_Expansion
From Word_Expansion
)
Select (Select s.word As sub
From groupedWords s
Where s.WordOID = n.WordOID
For Xml Path(''), Type)
From groupedWords n
Group By n.WordOID
For Xml Path('expansion')