$ifnullFirst   = $adapter->getIfNullSql('{{table}}.firstname', $adapter->quote(''));
    $ifnullMiddle  = $adapter->getIfNullSql('{{table}}.middlename', $adapter->quote(''));
    $ifnullLast    = $adapter->getIfNullSql('{{table}}.lastname', $adapter->quote(''));
    $concatAddress = $adapter->getConcatSql(array(
        $ifnullFirst,
        $adapter->quote(' '),
        $ifnullMiddle,
        $adapter->quote(' '),
        $ifnullLast
    ));

$ifnullFirst   = $adapter->getIfNullSql('{{table}}.firstname', $adapter->quote(''));
    $ifnullMiddle  = $adapter->getIfNullSql('{{table}}.middlename', $adapter->quote(''));
    $ifnullLast    = $adapter->getIfNullSql('{{table}}.lastname', $adapter->quote(''));
    $concatAddress = $adapter->getConcatSql(array(
        $ifnullFirst,
        $adapter->quote(' '),
        $ifnullMiddle,
        new Zend_Db_Expr('IF({{table}}.middlename IS NULL OR {{table}}.middlename="", "", " ")'),
        $ifnullLast
    ));