php zend framework2 sql execute query返回标量

Question

I have a query that i execute within zend framework 2

protected function getCityByZip($zip){
    $adapter = $this->getServiceLocator()->get('myConn');
    $sql = new Sql($adapter);
    $select = $sql->select();
    $select->from(array("cities" => "cities"))
           ->columns(array('cityName'))
           ->where(array("cityZip" => $zip));
    $statement = $sql->prepareStatementForSqlObject($select);
    $result = $statement->execute();
    return $result;
}

i want to do something like

executeScalar();

and get just a single value, and not a result set like i get here from using execute()

how is this possible?

Answer 1

I don't know if this is what you're looking for, but if you want your function getCityByZip($zip) returns a single value you can do this :

protected function getCityByZip($zip){
    $adapter = $this->getServiceLocator()->get('myConn');
    $sql = new Sql($adapter);
    $select = $sql->select();
    $select->from(array("cities" => "cities"))
           ->columns(array('cityName'))
           ->where(array("cityZip" => $zip));
    $statement = $sql->prepareStatementForSqlObject($select);
    $resultSet = $statement->execute();

    $current = $resultSet->current();

    return $current->cityName;
}

EDIT :

I think what you're looking for is the fetchOne() method which was in ZF1 DB Adapter (see this Fetching a Single Scalar from a Result Set) but not in ZF2. In ZF1 you could do this :

$db->fetchOne('SELECT cityName FROM users WHERE cityZip='.$zip);

But the equivalent, in ZF2, takes several lines of code as the above function.

Hope this could help.