IQ null values management

Hi,

I'm facing an issue with SAP Data Services & IQ with null values management.

I have a column containing nulls.

If i try to use a select * from table where column is null, i have a correct output with DBISQL.

When i use SAP Data Services with function like NVL() or restrictions like COLUMN IS NULL, i have no correct output.

It seems like DS can't identify null values.

Is there any configuration to be done in SAP IQ platform to correct this behavior ?

Thanks for your help,

Guillaume