Question

We have a source XML file that has an address node, and each node is supposed to have a zip_code node beneath in order to validate. We received a file that failed the schema validation because at least one node was missing it’s zip_code (there were several thousand addresses in the file).

We need to find the elements that do not have a zip code, so we can repair the file and send an audit report to the source.

--declare @x xml = bulkcolumn from openrowset(bulk 'x:\file.xml',single_blob) as s
declare @x xml = N'<addresses>
    <address><external_address_id>1</external_address_id><zip_code>53207</zip_code></address>
    <address><external_address_id>2</external_address_id></address>
</addresses>'

declare @t xml = (
select @x.query('for $a in .//address 
    return 
        if ($a/zip_code) 
            then <external_address_id /> 
        else $a/external_address_id')
)
select x.AddressID.value('.', 'int') AddressID
from @t.nodes('./external_address_id') x(AddressID)
where x.AddressID.value('.', 'int') > 0
GO

Really, it’s the where clause that bugs me. I feel like I’m depending on a cast for a null value to 0, and it works, but I’m not really sure that it should. I tried a few variations with the .exist function, but I couldn’t get the correct result.

Answer 1

If you just want to locate those nodes that are missing their <zip_code> element, you could use something like this:

SELECT
    ADRS.ADR.value('(external_address_id)[1]', 'int') as 'ExtAdrID'
FROM
    @x.nodes('/addresses/address') as ADRS(ADR)
WHERE
    ADRS.ADR.exist('zip_code') = 0

It uses the built-in .exist() method in XQuery to check the existence of a subnode inside an XML node.