I have had the same experience in VFP (not using NULL). This is why I love the command:
SET NULLDISPLAY TO ""
>So far I have worked with the Visual FoxPro Database. I rarely insert NULLs intentionally, they usually appear from the result of an outer join.
>
"The creative process is nothing but a series of crises." Isaac Bashevis Singer
"My experience is that as soon as people are old enough to know better, they don't know anything at all." Oscar Wilde
"If a nation values anything more than freedom, it will lose its freedom; and the irony of it is that if it is comfort or money that it values more, it will lose that too." W.Somerset Maugham
