使用会话ID从mySQL显示特定数据

Question

I'm trying to display the users first name after they login. They login using their email and password. Though, I would like to collect their first name and display it. Their name is in the same table that the email/password are in. Traditionally, I would use a session ID like this below.

<?php
session_start(); 
$_SESSION['first'] =  $first; 
?>

But this typically is for submitted data in a form and is used after the form has been authenticated. My question is, how would I gather data from the mySQl table rather than collecting it from the form and be able to have it has a session ID?... if that makes sense

Answer 1

Select the first name (and any other fields you desire) when checking the user name and password match.

if (!isset($_SESSION)) session_start();

$sql=sprintf("SELECT email, firstname FROM users WHERE email=%s AND password=%s", 
              $_POST["email"], $_POST["password"]);

//You'd better use parameterized query

$result = mysqli->query($sql);

$row = $result->fetch_assoc();

if(mysqli->num_rows > 0)
{
    $_SESSION["email"] = $row["email"];
    $_SESSION["firstname"] = $row["firstname"]; 
}
else 
{
 //operation for no matches
}