Mysql user can't update temp table (has all privileges)

Question

I try to execute the following query via php:

            CREATE TEMPORARY TABLE temp_table 
            AS 
            SELECT * FROM vacancies WHERE vacancyid = '22207';
            UPDATE temp_table SET vacancyid='22216' WHERE vacancyid='22207';
            INSERT INTO newdatabase.vacancies SELECT * FROM temp_table;
            DROP TEMPORARY TABLE temp_table;

This gives an error:

Errormessage: 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 'UPDATE temp_table SET vacancyid='22216' WHERE vacancyid='22207';

If i execute the query directly in PMA it works fine. The user I connect with in PHP has these priveliges:

GRANT ALL PRIVILEGES ON firstdatabase.* TO 'username'@'%' WITH GRANT OPTION;

GRANT ALL PRIVILEGES ON newdatabase.* TO 'username'@'%' WITH GRANT OPTION;

Anyone got a clue?

PHP code:

            //Get the new autoincrement id of the vacancy of individual jobboard
            $iNewId = $db->lookup("SELECT vacancyid FROM ".$aBoardInfo['username'].".vacancies ORDER BY vacancyid DESC LIMIT 1");
            $iNewId = $iNewId + 1;  

            $db->query("                                
        CREATE TEMPORARY TABLE temp_table 
        AS 
        SELECT * FROM vacancies WHERE vacancyid = '". $iVacancyid ."' ; 

        UPDATE temp_table SET vacancyid=". $iNewId ." WHERE vacancyid='". $iVacancyid ."' ; 

        INSERT INTO ".$aBoardInfo['username'].".vacancies SELECT * FROM temp_table ; 

        DROP TEMPORARY TABLE temp_table ;   
        ");

Answer 1

As it is described in the documentation in example 2

Example #2 SQL Injection

<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
$res    = $mysqli->query("SELECT 1; DROP TABLE mysql.user");
if (!$res) {
    echo "Error executing query: (" . $mysqli->errno . ") " . $mysqli->error;
}
?>

The above example will output:

Error executing query: (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 'DROP TABLE mysql.user' at line 1

Prepared statements

Use of the multiple statement with prepared statements is not supported.