NULL is the absence of any known value, think "I don't know." CHR(0) is a string of length one with all zero bits.
True or false? "I don't know." Length of the string? "I don't know." Number positive or negative? "I don't know." NULL is useful in statistics, and behaves correctly and consistently if used properly, but like a chainsaw, it's important to know which end to grasp. Sum of NULLs and non-NULLs? The sum of all the non-null values Average of a set of numbers? The average of all the non-null values. NULL is the SQL standard way of handling unknown values, while EMPTY() was xBASE (or was it Fox) specific hack. On Wed, Sep 30, 2015 at 10:21 AM, Ted Roche <[email protected]> wrote: > On Wed, Sep 30, 2015 at 5:18 AM, AndyHC <[email protected]> wrote: >> On 29/09/2015 23:49, Ken Dibble wrote: >>> >>> >>> .. .NULL. is a boolean value in VFP. >>> >> ... >> Now you've kicked my hobby-horse into life: >> - boolean null! - so the possible BInary values are 0, 1, and NULL? >> >> NULLs - don't talk to me about nulls, they always bite you in the ass.... >> mutter mutter.... >> > > Ha! No, Booleans in a able can also be EMPTY() so FoxPro logic is Four-State! -- Ted Roche Ted Roche & Associates, LLC http://www.tedroche.com _______________________________________________ Post Messages to: [email protected] Subscription Maintenance: http://mail.leafe.com/mailman/listinfo/profox OT-free version of this list: http://mail.leafe.com/mailman/listinfo/profoxtech Searchable Archive: http://leafe.com/archives/search/profox This message: http://leafe.com/archives/byMID/profox/cacw6n4vr_me7u2+ni-wibphwpx6dymesxekrqcvbr89azaf...@mail.gmail.com ** All postings, unless explicitly stated otherwise, are the opinions of the author, and do not constitute legal or medical advice. This statement is added to the messages for those lawyers who are too stupid to see the obvious.
