Question

this is table schema:

CREATE TABLE `USERS` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `email` varchar(30) DEFAULT '',
  `first_name` varchar(15) DEFAULT '',
  `last_name` varchar(15) DEFAULT '',
  `password` varchar(15) DEFAULT '',
  `gender` int(1) DEFAULT '-1',
  PRIMARY KEY (`id`)
)   

in php:

    $sql = 'INSERT INTO Users (email, first_Name, last_Name, password, gender ) VALUES                ("'.$email.'", "'.$first_name.'", "'.$last_name.'", "'.$password.'", '.$gender.')';

try {
    $db = getConnection();
    $stmt = $db->prepare($sql);  
    $stmt->execute();
    //$user = $stmt->fetchObject();
    echo 'last id was '.mysql_insert_id();

    $db = null;


    } catch(PDOException $e) {
            echo '{"error":{"text":'. $e->getMessage() .'}}'; 
    }

I can’t figure out why mysql_insert_id() returns 0. there are no other processes running. id is set to auto increment. Insert is done and seen in db.

Answer 1

You are using PDO to interface with the database. Use PDO::lastInsertId() to get the last inserted id.

$stmt->execute();
echo 'last id was ' . $db->lastInsertId();

mysql_insert_id() is part of the ext/mysql extension. You cannot mix-match functions from both extensions to interface with the same connection.