how to check variable if null?

jrahma

Hi,

I am using the following code to check if the $company_region is empty of NULL in the database but it's not working:

<?php if (!isset($company_region) || !empty($company_region) || !is_null($company_region)) { ?>
<tr>
    <td align="left" valign="top" style="width: 100px;"><b>State / City</b></td>
    <td align="center" valign="top" style="width: 20px;"><b>:</b></td>
    <td align="left" valign="top"><?php echo $company_region; ?></td>
</tr>
<?php } ?>

I tried all the combinations but I am still getting the row show on the page with a blank State/City! The value in the database is NULL when I run the stored procedure on the database itself.

What can I do?

Thanks
Jassim

bradgrafelman

The code you posted above attempts to use the variable if it is null (and then some - not sure why you're using three different functions when only one is necessary).

jrahma

bradgrafelman;11036749 wrote:
The code you posted above attempts to use the variable if it is null

I want the row to be shown if NOT null or empty that's why I I am saying !is_null

bradgrafelman;11036749 wrote:
and then some - not sure why you're using three different functions when only one is necessary).

I know 🙂 but I was trying to find where is the issue.

bradgrafelman

jrahma;11036755 wrote:
I want the row to be shown if NOT null or empty that's why I I am saying !is_null

But you're OR'ing that with !isset().

Simple example; say $company_region is truly set to the PHP NULL value (something you haven't confirmed, by the way, e.g. via [man]var_dump/man). Your if() statement:

if (!isset($company_region) || !empty($company_region) || !is_null($company_region)

is equivalent to:

if (TRUE || FALSE || FALSE)

which is, of course, evaluated as TRUE.

Simply put: you've managed to form an if() condition that can never evaluate to FALSE.

jrahma;11036755 wrote:
I was trying to find where is the issue.

Well... over-complicating the code by adding more and more function calls is an issue in and of itself, I'd say.

You haven't shown us how $company_region is defined, but I'm guessing that this piece of code will be executed after that variable is unconditionally assigned some value. So, isset() probably doesn't make much sense just based on semantics.

Next, note that [man]empty/man considers a lot more values than just NULL as 'empty', but you've only mentioned NULL. So, empty() doesn't work just based on your requirements.

Finally, we're left with [man]is_null/man, which makes the best fit not only based on requirements but semantics too. In other words: remove the other two functions and stick with the one that makes sense. (Then again, perhaps your requirements will change if and when you confirm that $company_region is actually NULL and not some other loosely-equivalent value.)

jrahma

but will is_null determine if the variable is empty (blank) - e.g "" or I have to make sure the vale in the database is NULL?

bradgrafelman

See the manual for [man]is_null/man and/or try it out yourself. Note, however, that "(blank)" doesn't really mean anything; "" is more specifically a string of length zero.

jrahma

it won't work! I tried it. So I'll have to use both !empty and !is_null.

Thank you so much again and have a nice weekend.

bradgrafelman

jrahma;11036769 wrote:
So I'll have to use both !empty and !is_null.

Er... not really, no; empty() covers a superset of the conditions is_null() checks, so if you're using empty() then is_null() is superfluous.

traq

jrahma;11036745 wrote:
I am using the following code to check if the $company_region is empty of NULL in the database …

Have you actually confirmed that the value is the mysql NULL value (and not, for example, FALSE, an empty string, or the word "null")?

MySQL NULL is understood by PHP as NULL.

jrahma;11036755 wrote:
I want the row to be shown if NOT null or empty that's why I I am saying !is_null

Do you mean "not null or empty" or "not null or not empty" (or, "not null and not empty")?

I suspect it's the last case? "not null and not empty" is the same as "not empty." If you know that [font=monospace]$company_region[/font] has been declared, you can simply use a truth test:

if( $company_region )

NogDog

Of possible use:

if(trim($variable) === '') {
    // $variable is either null, an empty string, or a string containing only white-space
    // it is not, however, an integer 0 or float 0
}