Check if a value is already in the table PHP/MYSQL - php

Question

I'd like to check if a value is already in the table.
The structure of my table is this:
ApplicantId = INT
EventId = INT
StudentId = INT
No need to use unique because these table has dependencies.
Below is what I have tried so far:
include('../connectdb.php');
$ScholarPointId = $_GET["ScholarPointId"];
$Point = $_GET["Point"];
$ScholarId = $_GET["ScholarId"];
$EventId = $_GET["EventId"];
$verifysql = mysql_query("SELECT EventId FROM scholar_attended_events WHERE ScholarId ='$ScholarId' ");
#$resultVerify = mysql_fetch_assoc($verifysql);
$num_rows = mysql_num_rows($verifysql);
if( $num_rows > 0 )
{
$script = "<script>
alert('The user has already attended this event!');
</script>";
header('updatescholarpoints.php');
exit();
}
else{
$result = mysql_query("UPDATE scholar_points
SET scholar_points.Points =
scholar_points.Points + $Point
WHERE scholar_points.ScholarPointId = '$ScholarPointId' ") or die(mysql_error());
mysql_query("INSERT INTO scholar_attended_events (EventId , ScholarId) VALUES( '$EventId' , '$ScholarId' ) ")
or die(mysql_error());
}
?>
What I want is to check if the EventId is already in taken by the Student = StudentId. If so, then system will prompt an alert box. Otherwise, Update and Insert into respective table. How can I do this? It seems I miss something in here. If you could help, I really appreciate it.

Answer 1

just missing an = ?
$verifysql = mysql_query("SELECT EventId FROM scholar_attended_events WHERE ScholarId =$ScholarId ");
(and use PDO or mysqli, your code is really in a deprecated mode)