SQL prepared statements - how to SELECT multiple rows - php

Question

I have this code so far
// Starts the transaction
self::$database->startTransaction();
try {
$sql = "SELECT playerId FROM players WHERE name=?";
$stmt = self::getConnection()->prepare($sql);
$stmt->bind_param('s', $playerName);
foreach ($playerNames as $key => $playerName) {
$stmt->execute();
$stmt->bind_result($playerId);
$stmt->fetch();
echo $playerId . "<br>";
}
// commits the transaction
self::$database->commit();
} catch (Exception $e) {
self::$database->rollback();
throw new Exception(__METHOD__." | ".$e->getMessage());
}
The array $playerNames contains the names of the players, e.g.
array('Player1', 'Player2', 'player3')
The code from above should select the playerId of those players from the database. I have some issues:
It just returns the last playerId (in this case the Id of 'player3'). I don't know why.
I use a foreach-loop to execute(). is this bad for the performance, if there were hundreds of names in the array?
In generell: Is this the correct approach for SELECTing or INSERTing stuff from or into a database?
I read this question: How can I prevent SQL injection in PHP?
But it didn't really work because of this:
$result = $stmt->get_result();
while ($row = $result->fetch_assoc()) {
// do something with $row
}
I get an error with the getResult()-method. It says, the method doesn't exist. I think my webspace doesn't support it and I can't install it manually. So I need to stick with fetch().
Or might it have other reasons?

Answer 1

$sql = "SELECT playerId FROM players WHERE name=?";
$stmt = self::getConnection()->prepare($sql);
$stmt->bind_param('s', $playerName);
$stmt->bind_result($playerId);
foreach ($playerNames as $key => $playerName) {
$stmt->execute();
$stmt->fetch();
echo $playerId . "<br>";
}
You are fetching results of only last execute
Running long loops is apparently bad for performance. Try to avoid them.
Yes, in general.