Sql Server table to XML with multiple child nodes

Question

I have the following table

name  | age | misc
------------------
david | 20  | foo
john  | 30  | bar

And I want to transform it into the following XML:

<doc>
  <field name="name" val="david" />
  <field name="age" val="20" />
  <field name="misc" val="foo" />
</doc>
<doc>
  <field name="name" val="john" />
  <field name="age" val="30" />
  <field name="misc" val="bar" />
</doc>

I have for this working below for a single column, however if I try to add a second column for another field node I get the error:

Msg 9303, Level 16, State 1, Line 25
XQuery [query()]: Syntax error near 'name', expected '}'.

This is a sample of what I am trying to do and is ready to run in SQL Server Management Studio. I can't find much documentation on the syntax and am quite lost for ideas.

Any assistance is appreciated!

declare @MyData table (name varchar(200), age varchar(200), misc varchar(200))

insert into @MyData values('david', '20', 'foo')
insert into @MyData values('john', '30', 'bar')

/*This one works fine*/
SELECT (select * from @MyData as MyData for xml auto, type).query
(
' for $d in /MyData
   return 
   <doc>{
     <field name="name" val="{data($d/@name)}"  />
  }</doc>'
)

/*This one is what I want*/
SELECT (select * from @MyData as MyData for xml auto, type).query
(
' for $d in /MyData
   return 
   <doc>{
     <field name="name" val="{data($d/@name)}"  />
     <field name="age" val="{data($d/@age)}"  />
     <field name="misc" val="{data($d/@misc)}"  />
  }</doc>'
)

Dog Ears · Accepted Answer · 2010-12-22 17:46:43Z

4

How about this..

select 
    (select 'name' as 'field/@name', a.name as 'field/@val' for xml path(''), type),
    (select 'age' as 'field/@name', a.age as 'field/@val' for xml path(''), type),
    (select 'misc' as 'field/@name', a.misc as 'field/@val' for xml path(''), type)
from 
    MyData a for xml path('doc')

for your XQuery version try this: (I just removed the curly braces) Is that OK?

SELECT (select * from @MyData as MyData for xml auto, type).query
(
' for $d in /MyData
   return 
   <doc>
     <field name="name" val="{data($d/@name)}"  />
     <field name="age"  val="{data($d/@age)}"  />
     <field name="misc" val="{data($d/@misc)}"  />
  </doc>'
)

answered Dec 22, 2010 at 17:46

Dog Ears

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1 Comment

amarsuperstar Over a year ago

I knew it was a simple syntax thing! I think I prefer the xquery version since I think it's a little more obvious what's happening. Thanks again

chezy525 · Accepted Answer · 2010-12-22 19:12:59Z

1

You're essentially trying to get XML for the unpivoted data. So, start by getting a unique row identifier that isn't a field (I'll use a CTE and row_number). From there, you can use UNPIVOT and FOR XML EXPLICIT:

;with data as (
    select name, age, misc,
        row_number() over(order by name) as 'row'
    from @MyData
)
select 1 as tag,
       null as parent,
       row as [doc!1!row!hide],
       null as [field!2!name],
       null as [field!2!val]
from data
UNION
select 2 as tag,
       1 as parent,
       row as [doc!1!row!hide],
       fieldName as [field!2!name],
       val as [field!2!val]
from data d
  UNPIVOT(val for fieldName in (name, age, misc)) up
order by row, tag
FOR XML EXPLICIT, ROOT('root')

the ROOT('root') is to add a simple root element and is in addition to the requested xml format, but I thought it might be useful.

UPDATE
After looking a bit closer at query execution plans, you might be better off simply creating formatted text then casting to xml:

select cast('<field name="name" val="'+name+'" />'+
            '<field name="age" val="'+age+'" />'+
            '<field name="misc" val="'+misc+'" />'
            as xml)
from @MyData
for xml path('doc')

edited Dec 22, 2010 at 19:12

answered Dec 22, 2010 at 18:25

chezy525

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1 Comment

amarsuperstar Over a year ago

Thanks for the answers. I was considering the second version if I would not get an xquery workaround, as it turns out I just needed to remove the braces! The unpivot looks interesting and may work well for another query I need!

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