Show login user column sum. error

Question

Good morning, everyone, help me? i do not understand much of php, but for me to finish my site missing only one thing: I need to post the sum of the values that are in the table but based on the logged in user, I already tried all the ways but I can not follow the last one I tested:

<?php    
    $_SESSION['usuario'] = 'user_login';
    $sql = $pdo->prepare("SELECT SUM(valor) AS total FROM investimentos WHERE usuario= usuario");

    //Passa o ID do usuário para a query
    $sql->bindValue(1, $_SESSION['user_login'], PDO::PARAM_INT);
    $sql->execute();
    $ln = $sql->fetchObject();
    echo $ln->total;    
?>

I’ve tried everything or take only column values without being logged in with you page is all blank.

Answer 1

I believe the problem lies in your query. At the end "WHERE user= user", the user is as a string. You need to leave it as a variable, like this: '$user'.

I’ve never used PHP this way, object oriented, but I think it should solve.

Answer 2

Do so:

$usuario = $_SESSION['usuario'];

$sql = $pdo->prepare("SELECT SUM(valor) AS total FROM investimentos WHERE usuario= $usuario");

Answer 3

I believe your problem is when passing the value to be replaced in the query.

$sql->bindValue(1, $_SESSION['user_login'], PDO::PARAM_INT);

The line above will replace the first character "?" of your query by the second parameter passed in the call of the bindValue method which in your case is $_SESSION['user_login'], however your query does not have the character "?". Therefore you should replace your query with the following:

$sql = $pdo->prepare("SELECT SUM(valor) AS total FROM investimentos WHERE usuario = ?");

Answer 4

Try replacing the PDO parameter this way:

<?php    
    $_SESSION['usuario'] = 'user_login';
    $sql = $pdo->prepare("SELECT SUM(valor) AS total FROM investimentos WHERE usuario= :usuario");

    //Passa o ID do usuário para a query
    $sql->bindValue(':usuario', $_SESSION['user_login'], PDO::PARAM_INT);
    $sql->execute();
    $ln = $sql->fetchObject();
    echo $ln->total;    
?>

make sure the session variable is coming right, add some var_dump or print_r to see what the value is, and move on.