Question

Please I need your help with my script. I’m trying to insert values into maintable, but before I insert, I have to check if a row have an exact match compared to the one I’m inserting. If there’s a match then it should echo Record Exists, and if not it should go ahead and insert into the table. The problem is that it is returning 0 for $duplicate, when actually there is a row that matches the entries that I’ve entered in the HTML page, thereby it goes ahead and inserts the duplicate.
Please what could the problem be?

{
    $query = mysql_query("SELECT m.matric_no, m.course_code, m semester_name, m.level, m.session 
                          FROM  maintable AS m 
                          WHERE m.matric_no = '".$matric_no."'
                          AND m.course_code = '".$course_code."'
                          AND m.semester_name = '". $semester_name."'
                          AND m.level = '".$level."'
                          AND m.session = '".$session."'") ;

    $duplicate = mysql_num_rows($query);

    if ($duplicate > 0 ) 
        echo "$duplicate" ;
    {
        echo "Record Exists"     
    }
    else
    {

        $query = "INSERT INTO maintable (matric_no, course_code, semester_nam,          session, level) 
                   VALUES ('".$matric_no."', 
                       '".$course_code."',
                       '".$semester_name."',
                       '".$session."', 
                       '".$level."')" ;
        mysql_query($query) or
            die (mysql_error());   

        echo"Record Inserted"; 
    }

Please forgive my formatting, I typed on a mobile, I didn’t mean disrespect to this community.

Answer 1

Your formatting’s a bit all over the place, which is why you’re finding it so hard to spot errors when they occur. Try sticking to a consistent format style. This should do the trick:

$check = mysql_query("SELECT * FROM maintable WHERE matric_no = '$matric_no' AND course_code = '$course_code' AND m.semester_name = '$semester_name' AND m.level = '$level' AND m.session = '$session'");

if(mysql_num_rows($check))
{
   echo 'Record exists!';
}
else
{
   $query = "INSERT INTO maintable (matric_no, course_code, semester_nam, session, level) VALUES ('$matric_no','$course_code','$semester_name','$session','$level')";
   mysql_query($query) or die (mysql_error());
}