| Subject | Re: Check for blank dates |
|---|---|
| Author | Adam |
| Post date | 2005-09-07T02:55:50Z |
--- In firebird-support@yahoogroups.com, "ra8009" <ra8009@y...> wrote:
NULL means undefined or unknown. Blank can refer to known but known
to be empty.
It might sound pedantic, but if you start having to deal with
strings, you will get very confused when you find that
WHERE STRINGFIELD = ''
and
WHERE STRINGFIELD IS NULL
return different results.
Assuming you understand all that, the way to find a NULL date is
WHERE DATEFIELD IS NULL
Adam
> How do I write a query that checks for blank using a statement inthe
> WHERE clause?There is no such concept as "blank". I assume you mean null dates.
NULL means undefined or unknown. Blank can refer to known but known
to be empty.
It might sound pedantic, but if you start having to deal with
strings, you will get very confused when you find that
WHERE STRINGFIELD = ''
and
WHERE STRINGFIELD IS NULL
return different results.
Assuming you understand all that, the way to find a NULL date is
WHERE DATEFIELD IS NULL
Adam