Null in Date Column

I was having one of those blunder moment when a few days ago I said that date column is not nullable. I was in SSIS, in a Derived Column transform and was writing something one of those conditional statements: “a ? b : c”. I put “null” in c and got an error hence my silly conclusion that date column is not nullable. But of course it is. Any column is nullable. And in SSIS it’s not “null”, but we write it using NULL functions, e.g. “NULL(DT_DBDATETIME)”.