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sqlsql-serversqlxmlxquery-sql

How to check that the XML element has the attribute with an empty string value

Is there a way to check that value of an element in the XML field has an empty size using SQLXML? Consider I have the following data in the column Conf of the table Test:

<Conf>
  <UserData>
    <data type="str" value="" />
  </UserData>
</Conf>

I can check that data exists by using the following SQL request:

SELECT Test.Conf.exist('/Conf/UserData/data') FROM Test;

But how can I check that data has an empty value? It could be something like the following, but it doesn't work:

SELECT Test.Conf.value('(/Conf/UserData/data/@value)[1]', 'nvarchar(max)')='' FROM Test;

My final solution is to use the following SQL statement:

SELECT Test.Conf.value('string-length(/Conf[1]/UserData[1]/data[1]/@value)', 'int') FROM Test;
Solution

  • Using XPath 1.0. string(@someattribute) test should return false if empty. I know nothing about SQLXML, but it will work if you can use a control sequence.