Insert NULL VALUES ($variable)

[fuzzy1]

Hey All,
How might I define $return_visits to insert a NULL value in the following php?

if($num_rows!='0'){$return_visits='yes';}
     else{$return_visits=NULL;}

$query ="INSERT INTO stattracker
	(browser,ip,date_visited,return_visits) VALUES
	('$browser','$ip',now(),'$page','$return_visits')" ;

[cahva]

You have to put it like this:

if($num_rows!='0'){$return_visits="'yes'";}
     else{$return_visits='NULL';}

$query ="INSERT INTO stattracker
    (browser,ip,date_visited,return_visits) VALUES
    ('$browser','$ip',now(),'$page',$return_visits)";

Mysql doesnt know about PHP null value so you have to write it as NULL.

[laserlight]

Actually, couldn't you just write:

$query ="INSERT INTO stattracker
    (browser,ip,date_visited) VALUES
    ('$browser','$ip',now(),'$page')";

I had the impression that unless otherwise specified, the default is always NULL.

[fuzzy1]

Thanks laserlight,
Overlooking the IF condition, yes you could write it like that. Sure.

Thanks cahva,
If I understand you correctly, your soulution hinges on single qoutes

1. To wrap in the definition -- $return_visits='NULL';
   AND

2. To OMIT in the values string of the insert query -- ('$browser','$ip',now(),'$page',$return_visits)";
   ???

I was under the impression that

1. $return_visits='NULL';
   Would simply insert the string 'NULL' as distinct from the MYSQL VALUE NULL
   AND THAT

2. AS A STRING, I would be required to WRAP the '$variable' in the $query
   ???

Hmmm... I'm off to experiment with that some more...

P.S. For a little beter context I have re-written the whole thing as follows... though I still belieive it can be refined and simplified.

	if($same_visit !='true'){
		$chk_return ="SELECT * FROM stattracker WHERE ip='$ip'AND date_visited < DATE_SUB(NOW(),INTERVAL 1 HOUR)";
		$result=mysql_query($chk_return); 
		$num_rows = mysql_num_rows($result);
			if($num_rows!='0'){
			$values="VALUES('$browser','$ip',now(),'$page','$from_page','$hostname','yes')";
			}
		}
		else{
			$values="VALUES('$browser','$ip',now(),'$page','$from_page','$hostname', NULL)";
			}
	//Insert hit data in stattracker table...
	$query_insert  ="INSERT INTO stattracker
	(browser,ip,date_visited,page,from_page,hostname,return_visits) $values";

[laserlight]

Overlooking the IF condition, yes you could write it like that. Sure.

Oh yes, I forgot about that, sorry.

AS A STRING, I would be required to WRAP the '$variable' in the $query

But you see, in this context NULL is not a string in the SQL statement, but a keyword.

[fuzzy1]

But you see, in this context NULL is not a string in the SQL statement, but a keyword.

Well, be that as it may...
Should the IF condition return true, $return_visits='yes' IS A STRING, and so being would cause a MYSQL ERROR for the INSERT. I haven't been able to make it work.

OH! Wait! I SEE IT NOW!!! $return_visits ="'yes'" NOT $return_visits='yes' duh....
Thanks to you both! I've GOT IT.