[RESOLVED] Can you help me with this IF statement bug?

fasterisbest

Hello,
Can anyone please tell me why this if statement will not default to the elseif statement?

          $sessionContent=$_GET['content_id'];
		  $theSession=$_GET['services_flash']; 

 if ((empty($theSession)) and (empty($theContent))) {

		$sessionContent=mysql_query("SELECT content_links FROM tbl_content WHERE content_page='services' AND content_start='yes'");
		$sessionResults=mysql_fetch_array($sessionContent);
		$fvStart = mysql_query("SELECT * FROM tbl_thumbs WHERE services_link='".$sessionResults['content_links']."' AND services_start='yes'");
		$fvResults = mysql_fetch_array($fvStart);
		$theSession = $fvResults['services_flash'];
		$_SESSION['flash_var'] = $theSession;
		$fv=$_SESSION['flash_var'];
		echo "session and content empty "; 

	} else if ((!empty($sessionContent)) and (empty($theSession))) {
		//$sessionContent=$_GET['content_id'];
		$sessionThumbs=mysql_query("SELECT content_links FROM tbl_content WHERE content_id='".$sessionContent."'");
		$sessionThumbsResult=mysql_fetch_array($sessionThumbs);
		$sessionFlash=mysql_query("SELECT services_flash FROM tbl_thumbs WHERE services_link='".$sessionThumbsResult['content_links']."' AND services_start='yes'");
		$sessionFlashResults=mysql_fetch_array($sessionFlash);
		$theSession = $sessionFlashResults['services_flash'];
		$_SESSION['flash_var'] = $theSession;
		$fv=$_SESSION['flash_var'];
		echo "session empty content isset ";

	} else{

		$theSession=$_GET['services_flash'];
		$_SESSION['flash_var'] = $theSession;
		$fv=$_SESSION['flash_var'];
		echo "nothing empty";
		}

I know all statements will work on their own. However, the else if statement will not execute when all statements run together.

Thanks. This is driving me crazy.

YAOMK

As long as your if statement is true, your elseif statement will not execute. Test your elseif by setting your if statement as follows:

if(1==0)
{
//.......
}
elseif 
//......

This way you can see if you are having issues with your if condition. Also note you should use AND or && not and.

laserlight

YAOMK wrote:
Also note you should use AND or && not and.

Keywords in PHP are not case sensitive, and and is consistent with if and else.

YAOMK

Yes... As I said "should". I believe AND is more readable than "and". Same thing with constants, CONSTANT_A is better practice than constant_b.

laserlight

YAOMK wrote:
I believe AND is more readable than "and".

Before you even raised this style issue, I actually arbitrarily used AND and OR in my own coding style, but it just occurred to me that such uppercase keywords are inconsistent with the lowercase keywords if and else. If indeed you regard AND as more readable than and, then you should also regard IF as more readable than if. Where style is concerned, consistency is important.

YAOMK wrote:
Same thing with constants, CONSTANT_A is better practice than constant_b.

That helps the constant names stand out from the keywords, but if you use uppercase keywords, then the constant names no longer stand out. I believe that it is also a relic from C, where constants were traditionally defined as preprocessor macros, which like defined constants in PHP, do not obey scope - without an all caps naming convention, there is a serious risk of confusion between variable/function names and macro names. In PHP this argument no longer applies since variable names are prefixed with '$', and since names are case insensitive collision with function names is still possible regardless of a case-based naming convention.

YAOMK

Laserlight, I completely agree with consistency. It is imperative to be consistent when doing serious web development.

You do have a solid argument in regards to the naming convention of constants. But every developer sooner or later will branch out to other languages, and in other languages such as ActionScript, Java etc, this becomes an issue. In these languages it is too easy to mistake variables with constants, so why not get it right the first time? even if it is technically feasible either way.

fasterisbest

Thanks for your efforts everyone. I have solved the puzzle.

I knew each statement was set up properly because I tested each one separately. For some reason the 1st "if" statement had to be moved to the "elseif" statement and vice versa. I'm not sure why they were not executing properly but now they do. I suppose the if statement was always true for some reason. Odd... I wasn't unsetting any variables. Anyway, thanks for your advice.

FASTERISBEST

laserlight

YAOMK wrote:
But every developer sooner or later will branch out to other languages, and in other languages such as ActionScript, Java etc, this becomes an issue. In these languages it is too easy to mistake variables with constants, so why not get it right the first time? even if it is technically feasible either way.

Indeed, but I hope that when a former PHP newbie branches out into another programming language he or she will adapt to that programming language instead of insisting that all the idioms and style conventions carried over from his or her experience in PHP must be the One True Way. For example, the logical and keyword in Python is not AND but and, while the boolean true literal is neither TRUE nor true but True. Or if you program in Eiffel, then CLASSES_ARE_DECLARED_LIKE_THIS, even though in many other programming languages only constants (and something only specially defined constants) are declared with such names.

fasterisbest wrote:
For some reason the 1st "if" statement had to be moved to the "elseif" statement and vice versa.

hmm... the code snippet that you provided gave the impression that $theContent was possibly defined in portion of script that was not shown. If this is not the case then clearly $theContent is not set, and variables that are not set are empty. Consequently, empty($theContent) is always true. This means that (empty($theSession) and empty($theContent)) is equivalent to empty($theSession). This would explain why you had to make such a swap.