PHP problem in the mysql query

[Slartibartfast]

Hi everyone, first time here and I hope you can help me. I'm just starting with php and I have a problem. I get an error back from my browser when I load a page, which worked perfectly before,:

"Database query failed: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1"

When adding this bit of code:

    function get_subject_by_id($subject_id) {
        global $connection;
        $query = "SELECT * ";
        $query .= "FROM subjects ";
        $query .= "WHERE id = {$subject_id}";
        //$query .= "LIMIT 1";
        $subject_set = mysql_query($query, $connection);
        confirm_query($subject_set);
        
        //if no rows are returned, then fetch_array will return false
        if ($subject = mysql_fetch_array($subject_set)) { 
            return $subject;
        }else{
            return NULL;
        }
    } 

I've been over it and over it but I can't figure out what I'm doing wrong. Any help would be apreciated.

[Derokorian]

In the function you never verify that there is something contained within $subject_id and if its empty, the query will be wrong.

Also note the whole mysql_* extension is outdated and due for deprecation, it is recommended you use mysqli_* or PDO

[Globalsupport]

you will definitly find a solution

[NogDog]

I find it's often useful to include the actual query string in the error output to help identify where the problem is. Therefore you might want to add an (optional?) parameter to your confirm_query() function so that you can pass it the query string, and then have it output that string in the error message.