Re: Nulls vs Blanks?

Posted in 1996

Robert Zook — 15 Jan 1996 23:59:10 GMT — source: Informix-list mailing list archive (1991-1998)

Keep in mind two things about nulls: you cannot put a null in a serial column, and if you run an aggregate function (AVG,SUM,MIN,or MAX) on a column with nulls the function will return a null. Likewise you cannot use a column with nulls in any sort of equation. Avoid using nulls then in these three cases: no nulls in a column defined as serial (the software will not allow it), no nulls in a primary key column, and no nulls in a column you plan on using in calculations. Rob Zook