Re: NULL values
| From: | Scotty Logan | Date: | Sat, 04 Dec 2010 02:56:23 +0000 |
| Subject: | Re: NULL values | ||
| References: | 1 | Groups: | php.db |
| Request: | Send a blank email to php-db+get-47521@lists.php.net to get a copy of this message | ||
On Fri, Dec 3, 2010 at 6:25 PM, Ron Piggott
<ron.piggott@actsministries.org> wrote:
>
> When I do the following query in mySQL only 1 record is retrieved.
>
> SELECT * FROM
paypal_payment_info WHERE
> os1 NOT LIKE 'commission_paid'
>
> I am surprised by this. This one record has no characters in it, but the “INSERT INTO”
> that created it used: ( os1 ) VALUES ( ‘’ ) instead of: (
> os1 ) VALUES ( NULL ) . There are a number of records where
> os1 is NULL. I would like these rows to retrieve as well. How do
> I make a WHERE clause for a cell that is NULL ?
>
You need to explicitly check for NULLs. The regular operators (<, >,
=, LIKE) work on values. NULL columns have no value, so you need to
use IS NULL or IS NOT NULL. Also, if you're not doing wildcard
matches, you should probably just use <> or =:
SELECT * FROM paypal_payment_info WHERE (os1 <>
'commission_paid'
OR os IS NULL)
Scotty