In the given PHP code, what are the potential pitfalls of not properly closing while loops or query statements?

Not properly closing while loops or query statements can lead to memory leaks, performance issues, and potential security vulnerabilities. It is crucial to always close these structures to free up resources and prevent potential errors or data leaks. To solve this issue, make sure to close while loops and query statements properly by using the appropriate closing statements or functions.

// Incorrect way of not closing while loop and query statement
$query = "SELECT * FROM users";
$result = mysqli_query($conn, $query);
while ($row = mysqli_fetch_assoc($result)) {
    echo $row['username'];
}

// Correct way of closing while loop and query statement
$query = "SELECT * FROM users";
$result = mysqli_query($conn, $query);
while ($row = mysqli_fetch_assoc($result)) {
    echo $row['username'];
}
mysqli_free_result($result);
mysqli_close($conn);