Zend Db Select “AND” problem

Question

I have the following select:

$select = self::getConnection()->select()
                           ->setSqlCalcFoundRows(true)
                           ->from(array('person' => parent::$_prefix . self::$_tableName), $rows)
                           ->where($wherePerson['statement'], $wherePerson['value'])
                           ->where($whereOwner['statement'], $whereOwner['value'])
                           ->order($sort .' '. $sortDir)
                           ->limit($limit, $offset);

Now i want to add an additional AND . But only if the field has a value (completed by the user). So when the owner field is empty, may not be the result of my query (see the AND):

SELECT SQL_CALC_FOUND_ROWS xxx
FROM xxxx AS xxxx
WHERE (person_id = '305000270002')
  AND (owner = '')
ORDER BY xxxx ASC
LIMIT 25

I don't need the AND if it is empty, otherwise my result is wrong.

Answer 1

Try the following:

$select = self::getConnection()->select()
                               ->setSqlCalcFoundRows(true)
                               ->from(array('person' => parent::$_prefix . self::$_tableName), $rows)
                               ->where($wherePerson['statement'], $wherePerson['value'])
                               ->where($whereOwner['statement'], $whereOwner['value'])
                               ->order($sort .' '. $sortDir)
                               ->limit($limit, $offset);

if (false === empty($theFieldToCheck)) {
    // add additional WHERE part if
    // a field IS NOT empty
    $select->where($additionalWherePart);
}

That creates that base statement and can be extended later by where() method on specific conditions.