Sql-server – How to update xml using value from a sql query

sql servert-sqlxml

I have a table with an XML column. I need to insert various nodes and then set those nodes using values from a sub-query.

Setup: 

use tempdb

CREATE TABLE [dbo].[Sites](
    [SiteID] [int] IDENTITY(1,1) NOT NULL,
    [SiteInfo] [xml] NULL,
    [InVal] Varchar(50) NULL)

insert into [dbo].[Sites] ([InVal]) select 'ABC' union select 'DEF' union  select 'GHI'

update [dbo].[Sites] SET [SiteInfo] = '<SiteInfo />'

update [dbo].[Sites] SET [SiteInfo].modify('insert <SiteID/> into (/SiteInfo[1])')

Here is my update in it's most simple form. 

update Sites SET [SiteInfo].modify('replace value of (/SiteInfo/@SiteID)[1] with sql:column("InVal")')

I have tried with both singleton and non singleton nodes

The end result should preferably not be a singleton. i.e something like: 

<SiteInfo>
  <SiteID>ABC</SiteID>
</SiteInfo>

Best Answer

You've got nothing to replace in <SiteID/>. Try and use an insert instead:

update Sites SET [SiteInfo].modify('insert text{sql:column("InVal")} as first into (/SiteInfo/SiteID)[1]');
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