The 1995 SQL Reunion: People, Projects, and Politics - System R: "Mike Blasgen: There were great controversies about NULL. Just to give you an example, if you don't know somebody's age, but you know a lot of other things about them and you want to record it in a database but you don't want to put in their age. So you leave it blank, but now you sort, say, on age. Where do you want that person's age to come out: at the beginning or the end or the middle? This is NULL theology. There are the people who want to eat the egg from the big end and people who want to eat it from the little end. And then there are people who want to eat it from the middle."