PHP MySQL SELECT Statement with bindparam doesn't work - php

Question

This is my code:
function getUsers($connection ,$username) {
$sql = "SELECT * FROM users where username = ?";
$stmt = $connection->prepare($sql);
$stmt->bindParam("s", $username, PDO::PARAM_STR);
return $stmt->fetchAll();
}
$voornaam = "dave";
$users = getUsers($connection, $voornaam);
print_r($users);
When I open my webpage, I get an empty Array.
I checked, and there is a user with the username "dave" in my database.
This should work, however, it doesn't...
Anyone knows what I did wrong?
Thanks in advance.

Answer 1

First is, you have to execute it before using fetchAll():
$stmt->execute();
$result = $stmt->fetchAll();
This is the correct way:
$stmt = $connection->prepare('SELECT * FROM users where username = :username');
$stmt->bindParam(':username', $username);
If you want to user ? it will determine the order of ? in bindParam, use it like this:
$sql = "SELECT * FROM users where username = ?";
$stmt = $connection->prepare($sql);
$stmt->bindParam(1, $username, PDO::PARAM_STR);
More example:
$sth = $dbh->prepare('SELECT name, colour, calories
FROM fruit
WHERE calories < ? AND colour = ?');
$sth->bindParam(1, $calories, PDO::PARAM_INT);
$sth->bindParam(2, $colour, PDO::PARAM_STR, 12);

Answer 2

Instead of using
$stmt->bindParam("s", $username, PDO::PARAM_STR);
you need to use
$stmt->bindParam(1, $username, PDO::PARAM_STR);
Check this link for details https://www.php.net/manual/en/pdostatement.bindparam
You need to check this Example #2 Execute a prepared statement with question mark placeholders
This is the correct way
$sql = "SELECT * FROM users where username = ?";
$stmt = $conn->prepare($sql);
$stmt->bindParam(1, $username, PDO::PARAM_STR);
$stmt->execute();
return $stmt->fetchAll();