更新具有相同ID和相同值的多行

Question

I have a simple update query, which somehow doesn't work. Already trying to change it for some time and compared it to other update-queries but no matter what I change, it does not function. Two rows in the same table with the same teacher_id should be updated with the same value.

Here is the query:

$StatusChangeQuery = "UPDATE teachers SET status_id = $status_id WHERE teacher_id = '20'";

$pdo->query($StatusChangeQuery);

I know it is a really simple one, but I keep getting the following error:

Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[42000]: Syntax error or access violation: 
1064 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 'WHERE teacher_id = '20'' at line 1' in /var/www/xxx/html/teacher.php:225 
Stack trace: #0 /var/www/xxx/html/teacher.php(225): 
PDO->query('UPDATE teachers...') #1 {main} thrown in /var/www/xxx/html/teacher.php on line 225

And the corresponding teachers rows look like:

+---+-------------+------------+
|id | teacher_id  | status_id  |
+---+-------------+------------+
| 1 |     20      |      1     |
| 2 |     20      |      1     |
+---+-------------+------------+

Answer 1

As the comments suggest, there is probably an issue with $status_id .

Since you are using PDO, it is advisable to prepare your statements.

$smt = $pdo->prepare("UPDATE teachers SET status_id=? WHERE teacher_id=?");
$smt->execute( array($status_id, 20) );