Re: 3vl 2vl and NULL
Date: Mon, 12 Dec 2005 04:21:37 GMT
Message-ID: <lV6nf.2620$Kk7.2076_at_trndny05>
"jason.glumidge_at_gmail.com" <Jason.Glumidge_at_gmail.com> wrote in message news:1134346574.162087.103130_at_g49g2000cwa.googlegroups.com...
> Hi Hugo, I wonder if that is a completely accurate comparison? For
> example if I say that spreadsheet cell A1 is empty and A2 = A1 + 7,
> then A2 resolves to 7. This seems much more analagous to a A1
> representing an empty string (like this pick that i keep hearing about
> on here). In a database a Null + anything would still be a Null - there
> seems a difference between non-existent and empty, RDBMS using the
> former, spreadsheets and pickies using the latter?
>
Spreadsheets use a "default value" of zero in the context you mentioned. But they don't always take an empty cell to be tantamount to zero.
Consider E5 = count (A1:D4)
count will count only the numbers in the box, not the empty cells.
Consider E6 = sum (A1:D4) / count (A1:D4) This will correctly compute the average of all the numbers inside the box, And will correctly gripe about division by zero if there are no numbers in the box. Received on Mon Dec 12 2005 - 05:21:37 CET