如何使用fetch函数只获取从数据库中获取的数据的一个值

Question

I am new to php and had chosen to stick to PDO format. I have been able to set up a workable registration and login system, but my challenge is fetching data from my database which would be used in other page of the user profile page I created. I had tried all the many examples and methods I was able to get on the internet but there are not working, or rather I don't know how to use it, where I want to insert the variable will still be empty. The only fetch function I was able to get will select all the row, for instance, if it is email, it will fetch all the registered emails in the database which is not suppose to be. The email should only be for the user whose profile is opened. Here are the codes. I am sure someone will help me figure this out. Thanks

    $data = $pdo->query("SELECT * FROM databaseName")->fetchAll();
    //this one is in the body where i want to insert the email
    foreach ($data as $row) {
    echo $row['email']."<br />
";
}

I tried everything my little knowledge of php but all to no avail. If i decide to use any other one, nothing will show.

Answer 1

You can try other alternative to achieve the same,

$stmt = $pdo->query('SELECT * FROM databasetable');
while ($row = $stmt->fetch())
{
    echo $row['email'] . "
";
}