[mysql-php]Cosa è meglio: aprire o chiudere una volte o tante volte?

[GoLBeZ]

    $mysql_access = mysql_connect($hostDB, $user, $pw);
    mysql_select_db($db, $mysql_access);
        $query = "SELECT * FROM tabella";
        $result = mysql_query($query, $mysql_access);
        if ($row = mysql_fetch_assoc($result)) {
                $id = $row["id"];
        }
    mysql_close($mysql_access);

    $mysql_access = mysql_connect($hostDB, $user, $pw);
    mysql_select_db($db, $mysql_access);
        $query = "SELECT * FROM tabella2";
        $result = mysql_query($query, $mysql_access);
        if ($row = mysql_fetch_assoc($result)) {
                $id = $row["id"];
        }
    mysql_close($mysql_access);
    

    $mysql_access = mysql_connect($hostDB, $user, $pw);
    mysql_select_db($db, $mysql_access);
        $query = "SELECT * FROM tabella3";
        $result = mysql_query($query, $mysql_access);
        if ($row = mysql_fetch_assoc($result)) {
                $id = $row["id"];
        }
    mysql_close($mysql_access); 

    $mysql_access = mysql_connect($hostDB, $user, $pw);
    mysql_select_db($db, $mysql_access);

        $query = "SELECT * FROM tabella";
        $result = mysql_query($query, $mysql_access);
        if ($row = mysql_fetch_assoc($result)) {
                $id = $row["id"];
        }

        $query = "SELECT * FROM tabella2";
        $result = mysql_query($query, $mysql_access);
        if ($row = mysql_fetch_assoc($result)) {
                $id = $row["id"];
        }

        $query = "SELECT * FROM tabella3";
        $result = mysql_query($query, $mysql_access);
        if ($row = mysql_fetch_assoc($result)) {
                $id = $row["id"];
        }
    mysql_close($mysql_access); 

Quale delle due "opzioni" è la migliore? grazie per la risposta...