INSERT INTO mysql php question

I have a php mysql tag cloud setup for my website. The issue is that it's storing stuff in database that have no values. How can I stop it from doing this. I need a command that will tell it to only store the info if there is a value for field 'term'... here is a snippet of the code.

$parse = parse_url($_SERVER['HTTP_REFERER']);
$se = $parse["host"];
$raw_var = explode("&", $parse["query"] );
foreach ($raw_var as $one_var) {
    $raw = explode("=", $one_var);
    $var[$raw[0]] = urldecode ($raw[1]);
}
$se = explode (".", $se);
switch ($se[1]) {
    case 'yahoo':
        $keywords = $var['p'];
        break;
    case 'aol':
        $keywords = $var['query'];
        break;
    default:
        $keywords = $var['q'];
}
unset($parse, $se, $raw_var, $one_var, $var);

mysql_query ("INSERT INTO tag_cloud (term, countyurl, cityurl, abbr) VALUES ('$keywords', '$countyurl', '$cityurl', '$abbr')");

PHP:

 

if ($keywords <> '')
{
mysql_query ("INSERT INTO tag_cloud (term, countyurl, cityurl, abbr) VALUES ('$keywords', '$countyurl', '$cityurl', '$abbr')");
}

PHP:

 

^above

or you could do

if(strlen($keyword) > 3)
{
...insert into database
}

that way single letters won't show up as tags.

 

Many web developer use this, instead of <>''
Anyway both will give same result.

if (!empty($keyword))
{
mysql_query ("INSERT INTO tag_cloud (term, countyurl, cityurl, abbr) VALUES ('$keywords', '$countyurl', '$cityurl', '$abbr')");
}

PHP:

Or you can use more advantage option with set of minimum string lenght, that have been posted by clinton

 

You should also sanitize your input.
http://php.net/mysql_escape_string

 

you can also use

if (trim($keywords) <> '')
{
mysql_query ("INSERT INTO tag_cloud (term, countyurl, cityurl, abbr) VALUES ('$keywords', '$countyurl', '$cityurl', '$abbr')");
}

trim function removes the space at the both ends.