That is because '' is not equal to null and therefore the first part
(sp_link is not null) satisfies the requirement.
Avi
On Monday, Jun 9, 2003, at 14:48 America/Chicago, Fernando Papa wrote:
>
> Hi all!
>
> I get a strange result with this query:
>
> SELECT count(*)
> FROM CONT_CAT
> WHERE id_instal = 2
> and id_cat = 2
> and (sp_link IS NOT NULL OR sp_link <> '')
>
>
> I have one row with an empty value ('') on sp_link, so, when I execute
> the query expect 0 on the result.
> I don't know why the result is 1.
> If I only put the last part ("sp_link <> ''") everithing goes ok.
> But I need to check both conditions, IF is null and IF is empty. And I
> can't understand why doesn't work.