未定义的最后插入的ID

Question

I need to get last inserted id

   $stmt = $db->query("SELECT LAST_INSERT_ID();");
   $row = $stmt->fetch();
   echo $row['id'];

js

    success: function(data) {
        console.log(data);
}

Result: undefined !

Answer 1

You must assign the proper alias

$stmt = $db->query("SELECT LAST_INSERT_ID() as id;");
$row = $stmt->fetch();
echo $row['id'];

otherwise echo $row['id'] is empty

Answer 2

LAST_INSERT_ID() returns the last id from a previous insert statement. If you want the most recently inserted record and are using Auto Increment Prime keys, you can use the code below:

SELECT MAX( id ) FROM table tablename; If you need to know what the NEXT id will be, you can get this from INFORMATION_SCHEMA

SELECT AUTO_INCREMENT FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = 'tablename'