What is the code for something thats not there?

[0o0o0]

example what comes after?? Ive tried == '' and == "0" and ==FALSE and ==NULL

if($id  ????????????????????

lol throw me a bone please.. ive tried every googled example

[laserlight]

You may be looking for [man]isset[/man] or [man]empty[/man], but that depends on what you mean by "something that's not there".

[vivek151189]

you might be looking for what laserlight suggestd
or you might b looking for somthing like thi s
if($d=="")

[cretaceous]

this maybe:
if($id!='')

or === for test against a 0

[0o0o0]

thanks guys its for this.. retrieving rows one at a time per page..

so maybe its a little more than IF ($id..

here..

$prev = "SELECT id, num FROM `mydb` WHERE `act` = 'Y' and id < $id ORDER BY id DESC LIMIT 1";


$result1 = mysql_query($prev)

 or die ("Couldn't execute query.");

   while ($row1 = mysql_fetch_array($result1))             

 {
 extract($row1);         

If($id == ''){  

echo "<img src=\"images/blank.png\" width=\"45\" height=\"45\" alt=\"Previous Listing\"  class=\"pic2\"/>";
}else{
echo "<a href=\"http://www.imgonnastickapeninmyeyeohmygod.com/test/".$num.".html\"><img src=\"images/backbutton.png\" width=\"45\" height=\"45\" alt=\"Previous Listing\"  class=\"pic2\"/></a>";

}
}

ps sorry I asked in my other thread also.. but made this one for directly related onlookers.

Your probably right "If($id == ''){ " doesnt work here.. whats my options? thankyou thankyou in advance.

Added: See I made blank image.pngs because if no NEXT button shows.. this code doesnt put and button image in... I like that it was a fluke.. but the entire site shifts ... so I needed to make an identical blank.png to hold the page together. I know sounds unstable but seems to work with all browsers out there firefox, safari, explorer, chrome.. so I need this blank.png to work in an else statement.

[0o0o0]

im a newbie all over again since 2005.. asked for an opinion on another thread, for getting single results from a db.. for one single page pagination like with Prev and Next buttons..

was given this reply

-- Get previous ID
SELECT id FROM myTable WHERE id < $id ORDER BY id DESC LIMIT 1

-- Get Next ID
SELECT id FROM myTable WHERE id > $id ORDER BY id ASC LIMIT 1

lol so im a a really slow crawl trying to work with this.

I had an idea it was entirely cancelling out when i tried every possible combo of '' empty results.. so I asked.

im in the newbies section for a reason. Im going to read up on what you told me I'll be back in 6 1/2 hours haha.. with a question.

Thanks for the direction! seriously. Thanks guys.

[0o0o0]

I really hate to ask, but this is the final part to my entire website.. and i can go play in the yard with the rest of the kids.

any help fixin this.. I have ZERO clue how to manipulate this.. as all my code from way way way back use while.

please!.. lol

$prev = "SELECT id, num FROM `mydb` WHERE `act` = 'Y' and id < $id ORDER BY id DESC LIMIT 1";


$result1 = mysql_query($prev)

 or die ("Couldn't execute query.");

   while ($row1 = mysql_fetch_array($result1))             

 {
 extract($row1);         

If($id == ''){  

echo "<img src=\"images/blank.png\" width=\"45\" height=\"45\" alt=\"Previous Listing\"  class=\"pic2\"/>";
}else{
echo "<a href=\"http://www.imgonnastickapeninmyeyeohmygod.com/test/".$num.".html\"><img src=\"images/backbutton.png\" width=\"45\" height=\"45\" alt=\"Previous Listing\"  class=\"pic2\"/></a>";

}
}

when I change this it errors on {

set me straight on what I need here just here.. thanks...

 or die ("Couldn't execute query.");

   while ($row1 = mysql_fetch_array($result1))             

 {
 extract($row1);         

[0o0o0]

"rookie speghetti"

$prev = "SELECT id, num FROM `myDB` WHERE `act` = 'Y' and id < $id ORDER BY id DESC LIMIT 1";
$next = "SELECT id, num FROM `myDB` WHERE `act` = 'Y' and id > $id ORDER BY id ASC LIMIT 1";

$result1 = mysql_query($prev)

 or die ("Couldn't execute query.");

$rowp = mysql_num_rows($result1);

if ($rowp == 0){

echo "<img src=\"images/endpage.png\" width=\"45\" height=\"45\" alt=\"Previous Listing\"  class=\"pic2\"/>";

} else {

   while ($row1 = mysql_fetch_array($result1))             

 {
 extract($row1);         


echo "<a href=\"http://www.mysite.com/test/".$num.".html\"><img src=\"images/back12.png\" width=\"45\" height=\"45\" alt=\"Previous Listing\"  class=\"pic2\"/></a>";



 }
}


$result2 = mysql_query($next)

 or die ("Couldn't execute query.");

$rown = mysql_num_rows($result2);

if ($rown == 0){

echo "				<div><img src=\"images/endpage.png\" width=\"45\" height=\"45\" alt=\"Next Listing\" class=\"pic3\" />";


} else {

   while ($row2 = mysql_fetch_array($result2))             

 {
 extract($row2);         

echo "                    	 <div><a href=\"http://www.mysite.com/test/".$num.".html\"><img src=\"images/fwd12.png\" width=\"45\" height=\"45\" alt=\"Next Listing\" class=\"pic3\"/></a>";



 }

}

laugh all ya want, this is the newbie section. But its somehow workin..

is it correct?? can it be cleaner?? thanks last crazy question on here for a few months.

[Derokorian]

First thing I would say is you need to stick to a single way of doing braces, proper indentation etc. As such without changing the function or the code itself (but rather just the spacing) I would have it look like this (note Using PHP tags for highlighting, you should do this too on these boards). Note I also changed some variable names so they are more descriptive (and therefore more useful to you, the programmer) also removed the loops that don't make sense really (as BG pointed out).

$prev = "SELECT id, num FROM `myDB` WHERE `act` = 'Y' and id < $id ORDER BY id DESC LIMIT 1";
$next = "SELECT id, num FROM `myDB` WHERE `act` = 'Y' and id > $id ORDER BY id ASC LIMIT 1";

$resultPrev = mysql_query($prev) or die ("Couldn't execute query.");

if( mysql_num_rows($resultPrev) == 0 ) {
	echo "<img src=\"images/endpage.png\" width=\"45\" height=\"45\" alt=\"Previous Listing\"  class=\"pic2\"/>";
} else {
   $rowPrev = mysql_fetch_assoc($resultPrev);
	echo "<a href=\"http://www.mysite.com/test/".$rowPrev['num'].".html\"><img src=\"images/back12.png\" width=\"45\" height=\"45\" alt=\"Previous Listing\"  class=\"pic2\"/></a>";
}

$resultNext = mysql_query($next) or die ("Couldn't execute query.");

if( mysql_num_rows($resultNext) == 0 ) {
	echo "				<div><img src=\"images/endpage.png\" width=\"45\" height=\"45\" alt=\"Next Listing\" class=\"pic3\" />";
} else {
   $rowNext = mysql_fetch_assoc($resultNext);
	echo "                    	 <div><a href=\"http://www.mysite.com/test/".$rowNext['num'].".html\"><img src=\"images/fwd12.png\" width=\"45\" height=\"45\" alt=\"Next Listing\" class=\"pic3\"/></a>";
}

Also you can delimit strings with single quotes so you don't have to escape double quotes within the string (AKA those echos). There is another thing that doesn't make sense as well: The fact that you use the 'num' column to build your link, but you based the query off of the id.

I wouldn't use query or die statements either, I prefer to check if the $result variable is false instead, something like this:

$qry = "SELECT 1 as num";
$res = mysql_query($qry);
if( $res === FALSE ) {
   echo "Query failed: $qry<br>Error: ". mysql_error();
} elseif( mysql_num_rows($res) == 0 ) {
   echo "No rows found.";
} else {
   while( $row = mysql_fetch_assoc($res) ) {
      echo $row['num'];
   }
}

Also note, the entire mysql library has been deprecated in favor of mysqli (the i stands for improved) or PDO (PHP Data Objects). I only used it in my example so as not to throw more confusion on you, but you really NEED to use the proper library. See Choosing an API for more info.