Selecting null value from XML in SQL Server

Question

I\'m trying to select from XML that has a null as one of the attributes. Instead of returning a null, it returns a 0. What am I doing wrong?
See code below to replicate:

Answer 1

Because you are setting the fields to INT you have the problem that both xsi:nil="true" fields and the value 0 will end up as 0 as the default value for INT Is 0.

You could convert to VARCHAR first to detect the empty string ('') that string fields containing xsi:nil="true" produce and then convert the result to INT.

This SELECT will give you the answer you are after

SELECT  CONVERT(INT,NULLIF(ParamValues.TaskChainerTask.query('Property1').value('.', 'varchar(5)'),'')) AS Property1
      , CONVERT(INT,NULLIF(ParamValues.TaskChainerTask.query('Property2').value('.', 'varchar(5)'),'')) AS Property2
FROM    @a.nodes('(/TestSet/Element)') AS ParamValues (TaskChainerTask) 

The result of this gives you:

Property1   Property2
1           1
NULL        2
3           3