how to fetch all user data from database? - php

Question

i want fetch all users data but am getting only one user details, please help me to solve
$conn = mysqli_connect("localhost", "root", "", "bitmining");
$sql6="SELECT username FROM users";
if($result = mysqli_query($conn, $sql6)){
while ($row=mysqli_fetch_array($result)){
//Hashrate Data Fetch
$investedusername = $row['username'];
$sql3="SELECT sum(hashrate_amount) as total FROM buyhashrate WHERE invested_username='$investedusername'";
$result = mysqli_query($conn, $sql3);
$row = mysqli_fetch_assoc($result);
//Total Value of Hashrate
echo $row['total'] . " GH/s";
echo "<br />";
}
$result->close();
}

Answer 1

Your re-using the $result field, change your second reference to something like ...
$result1 = mysqli_query($conn, $sql3);
$row = mysqli_fetch_assoc($result1);
This will stop it reseting the value your using for your main loop in
while ($row=mysqli_fetch_array($result)){

Answer 2

You use the $result variable for both mysqli_query
$result = mysqli_query($conn, $sql3);

Answer 3

While other answers are right about your mistake, I want to give you a better solution.
Try to use a join like this:
$conn = mysqli_connect("localhost", "root", "", "bitmining");
$sql="SELECT SUM(hashrate_amount) AS total FROM users AS t1 LEFT JOIN buyhashrate AS t2 ON (t1.username=t2.invested_username) GROUP BY t1.username";
if($result = mysqli_query($conn, $sql)){
while ($row=mysqli_fetch_array($result)){
//Total Value of Hashrate
echo $row['total'] . " GH/s";
echo "<br />";
}
$result->close();
}
This way you do just one query from database. But using your method you have n+1 queries which n is the number of users. So for one hundred users there is 101 queries.