How to test for empty date from MySql call?

Wysocki · 02-06-2005, 12:45 PM

Code:

$result=mysql_query("SELECT * FROM sk_recvitem WHERE 1");
$shipdate=mysql_result($result,1,"shipdate");
if ($shipdate = "0000-00-00") $shipdate="NONE";

I have the above code accessing a MySql database to return a date field so I can place it on my webpage. If the date field has not been set, the value in $shipdate shows up as 0000-00-00 but I'd like the field to show NONE. The above IF test ALWAYS evaluates to true though. I can't use empty($shipdate) because it appears to contain 10 characters. How should I test for this?

redhead · 02-06-2005, 12:56 PM

Quote:

Code:

if ($shipdate = "0000-00-00") $shipdate="NONE";

Should be:

Code:

if ($shipdate == "0000-00-00") $shipdate="NONE";

or

Code:

if ($shipdate === "0000-00-00") $shipdate="NONE";

in your case it's if $shipdate can be assigned the value "000-00-00" which will allways be true.

Wysocki · 02-06-2005, 01:00 PM

Duh!! Thanks for the quick reply. I'm new to php so I keep confusing it with syntax from all the other languages I've worked with.

idx · 02-06-2005, 01:17 PM

Redhead has you covered there, but I'll be a syntax nazi for a bit..

- It's always good practice to put your literal first in a comparison to avoid this very scenario.
eg:

PHP Code:


			
if ('0000-00-00' = $shipdate) {

   $shipdate = 'NONE';

}

So even if you use = instead of == it'll evaluate as false and you'll find the problem earlier. Plus, if you have a large conditional statement, your literal will be in at the front and easier to read.

- One-liners are never good for code maintainability.
Not very clear:

PHP Code:


			
if ('0000-00-00' == $shipdate)

   $shipdate = 'NONE';

   func1();

   func2();

   //etc..

much better:

PHP Code:


			
if ('0000-00-00' == $shipdate) {

   $shipdate = 'NONE';

}

   func1();

   func2();

   //etc..

-r