gistfile1.txt

// given that you have created UserMapper and AddressMapper,
// and set up a 1:1 relationship from UserMapper to AddressMapper named 'address':

$atlas
    ->select(UserMapper::CLASS) // "FROM user"
    ->joinWith('address') // the name of the relationship field
    ->cols([
        'user.id AS id',
        'user.name AS name',
        'address.id AS address_id', // aliased using the relationship field name
        'address.street AS street',
        'address.city AS city',
    ])
    ->where('user.name = ?', 'romanb');
    ->fetchAll();

// Cf. http://atlasphp.io/mapper/direct.html#1-9