Re: 'hello world' != '' does not work?

The '' is interpreted as a NULL. Any comparison against a null value (even != ) is considered false.

Some ways around it: check for LENGTH('hello world') > 0, or use the function result NVL('hello world', 'value to use if first value is null').

John

On Fri, 16 Mar 2001 23:21:53 GMT, jeffreyb_at_gwu.edu (Jeffrey Boulier) wrote:

>
>Hi folks,
>
> We're running into a strange problem with != . It works for
>numerics, but not for strings.
>
>produser_at_PROM> select sysdate from dual where 1 != 0;
>
>SYSDATE
>---------
>16-MAR-01
>
>user_at_DB> select sysdate from dual where 'hello world' != '';
>
>no rows selected
>
>Any thoughts? Is != not valid for comparing strings in Oracle, or have we
>run into a bug? Our database is 8.1.6.3.
>
> Yours Truly,
> Jeffrey Boulier

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