select insert if not exist add or update - mysql

Question

im trying to log searches that happen on my website. when someone searches for something i want to first check the database if it has been searched before. if it has add +1 count to the number of searches if it hasnt submit it to the database.
the problem im getting at the moment is anytime you search it updates all logged search terms. i presume becuse i havent set an id. how can i get the id of the search term in the first select query and pass the id as a variable in the second query so it only updates the searchterm associated with that id?
$result = mysql_query("SELECT * FROM wss_search WHERE searchterm ='$trimmed' ");
if( mysql_num_rows($result) > 0) {
mysql_query("UPDATE wss_search SET count = count+1 WHERE searchterm = '$trimmed' ");
}
else
{
mysql_query("INSERT INTO wss_search (id, searchterm, count) VALUES ('NULL', '$trimmed', '1') ");
}
any help very much appreciated.
im also aware that i should be using mysqli but the rest of the software hasnt been update to mysqli yet.

Answer 1

Ive got it working using the below code. im new to php could you please tell me why its not secure and what i need to do to make it secure?
$var = $_GET['q'] ;
$trimmed = mysql_secure($var);
$result = mysql_query("SELECT id FROM wss_search WHERE searchterm ='$trimmed' ");
while($row = mysql_fetch_array($result)) {
$id = $row['id'];
}
if( mysql_num_rows($result) > 0) {
mysql_query("UPDATE wss_search SET count = count+1 WHERE id = '$id' and searchterm = '$trimmed' ");
}
else
{
mysql_query("INSERT INTO wss_search (id, searchterm, count) VALUES ('NULL', '$trimmed', '1') ");
}