PHP PDO fatal error

I have the following query:

$sql  = "UPDATE db.users SET $str WHERE users.{$this->row} = {$this->value} LIMIT 1"; 

Which echo's out:

UPDATE db.users SET username=testUser, gid=3 WHERE users.username = mmiller LIMIT 1 

However when I do:

$count = Db::init()->exec($sql);

I get:

Fatal error: Uncaught exception 'PDOException' with message

'SQLSTATE[42S22]: Column not found: 1054 Unknown column 'mmiller' in 'where clause''开发者_运维技巧 in /class.php:185 Stack trace: #0 /class.php(185): PDO->exec('UPDATE db...') #1 /class.php(194): User->modify('username', 'gid', 'testUser', '3') #2 {main} thrown in /class.php on line 185

Any ideas?

You need to use "

UPDATE db.users SET username="testUser", gid="3" WHERE users.username = "mmiller" LIMIT 1 

Make sure your echo shows you that. You could use ' ofcourse, whatever floats your boat :)

You need to use quotes around string values;

 $sql = "UPDATE db.users SET $str WHERE users.{$this->row} = '{$this->value}' LIMIT 1";

Seeing you're already using PDO, it might be beneficial to use prepared statements. Although a bit slower for a one-off query, it increases security and handles all escaping necessary, so you won't run in to these problems.