How can I Select the MAX of a Column using Zend_Db_Table?

You can run direct sql, using $db->query(); yours would simply be:

$db->query("SELECT MAX(id) AS maxID FROM myTable");

but if you want the object notation, then you'd do something like this:

$db->select()->from("myTable", array(new Zend_Db_Expr("MAX(id) AS maxID")));

For those looking to just select the max id from their id column in Zend Framework 2 (maybe 3 as well), but getting this error...

While processing primary key data, a known key id was not found in the data array

...note that you'll need to alias MAX(id) as id.

Example inside a table extended from the TableGateway class:

$select = $this->sql->select();
$select->columns(['id' => new Expression('MAX(id)')]);
$maxId = $this->selectWith($select)->current()->id;
return (int) $maxId;

You need to use Zend_Db_Expr to use mysql functions:

return $this->fetchAll(
            $this->select()
                ->from($this, array(new Zend_Db_Expr('max(id) as maxId')))
            )
    );