'' will auto convert to numeric 0 which will autoconvert to the "zero date" which is 1/1/1900. I am pretty sure that it was this way back in the 80s with Sybase and I think this might be Sybase legacy. That is far enough back in the past that I am a bit foggy on my memory of that. In any case the expected behavior is that both an empty and a blank string are autoconverted to 1/1/1900.