how to retrive data from database using mysqli_fetch_array in php - php

Question

How can retrive data.here login not working.I used mysqli_fetch_array,but before while the condition failed.
<?php
session_start();
include 'db.php';
$username = $_POST['username'];
$password = $_POST['password'];
$query = mysqli_query($connect,"SELECT * FROM tbl-login where username='".$username."'");
$n = 0;
while($row = mysqli_fetch_array($query)) {
// $u-id = $row['u-id'];
$dbusername = $row['username'];
$dbpassword = $row['password'];
$usertype = $row['usertype'];
$_SESSION['usname'] = $dbusername;
$_SESSION['uid'] = $u-id;
$_SESSION['usertype'] = $usertype;
if ($dbusername == $username && $dbpassword == $password) {
$n++;
echo "grtet";
// header('location:dashboard.php');
}
}
if ($n == 0) {
header('location:index.php');
}
?>

Answer 1

$query = mysqli_query($connect,"SELECT * FROM tbl-login where username='".$username."' and password='".$password."'");
$row = mysqli_fetch_row($query); // Just ONE row, because expecting is, there is only one user with this USERNAME
if(empty($row)) {
echo 'Invalid username or password';
}else{
echo 'OK :)';
}

Answer 2

When you're not sure what makes a query fail, call mysqli_error(). While I haven't tested myself, I believe tbl-login is the cause of the error (which mysqli_error() should return if you call it).
MySQL allows spaces and non-identifier characters to be table/column name, but when referring to such a name, you need to enclose it between backtick (`). Hence tbl-login should be written as `tbl-login` in the SQL query.

Answer 3

You Have Created table name as tbl-login, column name as u-id and variable as $u-id, which i think is a problem. If Possible, change your column name, table name and variable name. Here are some links to get basic idea for creating variable name, column name, table name.
Create Variables, Create Table, Identifiers
I've updated your code. Please have a look.
<?php
session_start();
include 'db.php';
$username = $_POST['username'];
$password = $_POST['password'];
$query = mysqli_query($connect,"SELECT * FROM `tbl_login` WHERE username='$username' AND password='$password'");
$rowcount = mysqli_num_rows($query);
if($rowcount > 0) {
while($row = mysqli_fetch_array($query,MYSQLI_ASSOC)) {
$_SESSION['usname'] = $row['username'];
$_SESSION['uid'] = $row['u_id'];
$_SESSION['usertype'] = $row['usertype'];
header('location:dashboard.php');
}
} else {
header('location:index.php');
}
?>