IFNULL-Function / Date-Type

Hello,

I do have a simple question: how to use the IFNULL-Funktion in a HANA-SQL-Statement.

I do not know what HANA is expecting as second parameter in case of date-types.

This example works fine:  CASE WHEN IFNULL("CardName", 'n') = 'n' THEN ....

When I use it like that: CASE WHEN IFNULL("ShipDate", 0) = 0 THEN... HANA answer is "SAP DBTech JDBC: [2048]: column store error: logical index creation error:  [2052] attribute type is invalid "

As second parameter I tried 0, 'n', NULL. Run out of ideas... Can anyone help me?

Thanks in advance :-)

Regards, Toby