How can I query a value in SQL Server XML column

sql, sql-server, xml, xquery

Solution

select
  Roles
from
  MyTable
where
  Roles.value('(/root/role)[1]', 'varchar(max)') like 'StringToSearchFor'

In case your column is not `XML`, you need to convert it. You can also use other syntax to query certain attributes of your XML data. Here is an example...

Let's suppose that data column has this:

<Utilities.CodeSystems.CodeSystemCodes iid="107" CodeSystem="2" Code="0001F" CodeTags="-19-"..../>

... and you only want the ones where `CodeSystem = 2` then your query will be:

select 
  [data] 
from
  [dbo].[CodeSystemCodes_data]
  
where
  CAST([data] as XML).value('(/Utilities.CodeSystems.CodeSystemCodes/@CodeSystem)[1]', 'varchar(max)') = '2'

These pages will show you more about how to query XML in T-SQL:

Querying XML fields using t-sql

Flattening XML Data in SQL Server

EDIT

After playing with it a little bit more, I ended up with this amazing query that uses CROSS APPLY. This one will search every row (role) for the value you put in your like expression...

Given this table structure:

create table MyTable (Roles XML)

insert into MyTable values
('<root>
   <role>Alpha</role>
   <role>Gamma</role>
   <role>Beta</role>
</root>')

We can query it like this:

select * from 

(select 
       pref.value('(text())[1]', 'varchar(32)') as RoleName
from 
       MyTable CROSS APPLY

       Roles.nodes('/root/role') AS Roles(pref)
)  as Result

where RoleName like '%ga%'

You can check the SQL Fiddle here: http://sqlfiddle.com/#!18/dc4d2/1/0

Problem

I have following XML stored in a XML column (called `Roles`) in a SQL Server database. ``` <root> <role>Alpha</role> <role>Beta</role> <role>Gamma</role> </root> ``` I'd like to list all rows that have a specific role in them. This role passed by parameter.

Original source