What is the common mistake in the PHP code provided in the forum thread?

The common mistake in the PHP code provided in the forum thread is that the variable `$result` is being assigned the result of the `mysqli_query()` function directly, which will return a resource object, not the actual data from the query. To solve this issue, you need to fetch the data from the result resource using a function like `mysqli_fetch_assoc()`.

// Incorrect code
$result = mysqli_query($connection, "SELECT * FROM users WHERE id = 1");
$row = $result; // This line is incorrect

// Corrected code
$result = mysqli_query($connection, "SELECT * FROM users WHERE id = 1");
$row = mysqli_fetch_assoc($result);