multiple update using ajax with php - php

Question

hey guys im trying to update my database using php ang ajax, but assuming that the textbox are dynamic thats why im trying to update the database using multiple updates with one click of a button but my fire bug says that "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 '= '100' WHERE student_id = '33' AND subject_id = '2' AND school_id = '1' AND adv' at line 1 " im not pretty sure with my code because im just experimenting on how to do it in ajax with php.
PHP:
session_start();
$school_id = $_SESSION['school_id'];
$faculty_id = $_SESSION['user_id_fac'];
$subject_id = $_POST['subject_id'];
$year_grade_level = $_POST['year_level'];
$subject_handeler_id = $_POST['subject_handler_id'];
$student_grades_boy = $_POST['student_grades_boy'];
$student_grades_girl = $_POST['student_grades_girl'];
$update_grades_boys = "UPDATE registrar_grade_archive SET";
//SET status = '0' WHERE subject_id = '$subject_id'"
$vaues_girl = array();
$values_boy = array();
foreach ($student_grades_boy as $key=>$data) {
$student_id_B= $data['studnt_B_id'];
$grade_B = $data['studnt_grade_B'];
$values_boy[$key] = 'grade = \''.$grade_B.'\' WHERE student_id = \''.$student_id_B.'\' AND subject_id = \''.$subject_id.'\' AND school_id = \''.$school_id.'\' AND advisor_faculty_id = \''.$faculty_id.'\' AND subject_handler_id = \''.$subject_handeler_id.'\' ' ;
}
$values_boy = implode(', ', $values_boy);
$ready_edit_grades_boy = $update_grades_boys . $values_boy;
$save_grades_boy = mysql_query($ready_edit_grades_boy) or die(mysql_error());
please help guys. thanks in advance

Answer 1

Some problems here:
if $student_grades_boy contains more than 1 item, your sql will have multiple WHERE statements (you can only have 1);
you need a space between SET and the column name;
you have a serious sql injection problem;
you should switch to PDO or mysqli as the mysql_ functions are deprecated.

Answer 2

It appears you have no space between SET and grade.
Adding a space here should do the trick:
$update_grades_boys = "UPDATE registrar_grade_archive SET ";
If this doesn't do it, it would help tremendously if you could post the result of echo $ready_edit_grades_boy; and update your question.

Answer 3

try
$update_grades_boys = "UPDATE registrar_grade_archive SET ";
One space is needed after SET..

Answer 4

You are not escaping vars, so it could be some ' or " in your values.
http://php.net/manual/en/mysqli.real-escape-string.php