[PHP / MySQL]：循环中的预处理语句

Question

My problem seems like a rather small one to me, yet, I cannot figure out a proper solution. The Setup: I have a table 'city_locations' with the columns 'country', 'city', 'longitude', 'latitude'. The countrys are given by 2-Letter ISO codes. I want them to be full names.

For this, I have imported the table 'countrycodes', containing only the columns 'name' and 'code'.

$namechange = $con->prepare("UPDATE city_locations SET country=? WHERE country=?");

$list = $con->prepare("SELECT name, code FROM countrycodes");
$list->execute();
$list->bind_result($name, $code);

$namechange->bind_param('ss', $name, $code);

while ($list->fetch()){
    while ($namechange->execute()) {}
    echo "$code is now $name <br>";
}

I succesfully retrieve all pairs in the (outer) while loop.

$namechange->execute(); however doesn't do anything - I tried it with and without the while loop, tried using LIMIT 0, 10000 in the query (though I'm not entirely sure I understand LIMIT right). With and without the while loop, the statement doesn't do anything. With LIMIT 0, 10000 the statement cannot be preapred properly (gives an error).

I also tried to bind the params new in every step of the while loop - didn't seem to do anything either.

When running the same command from my web interface, it works fine. However, in that case, I have to type all 200+ codes manually. Seems like a bit much work.

Thanks a lot for your help, Kjeld.

EDIT: $con is of type mysqli.

Answer 1

$namechange = $con->prepare("UPDATE city_locations SET country=? WHERE country=?");
$list = $con->prepare("SELECT name, code FROM countrycodes");
$list->execute();
$list->bind_result($name, $code);



while ($list->fetch()){
    $namechange->bind_param('ss', $name, $code);
    $namechange->execute();

    echo "$code is now $name <br>";
}

it will probably solve your problem.