mysql - PHP Only Selecting First Row? -

i have quick login form made school problem when try , login worked when want log first user (username: hbutler password: password) when try login other accounts page refresh have set if incorrect here code :

<?php  //create connection… //("where database is", 'database login' , 'database password' , "database name") $con=mysqli_connect("", 'root', 'root', "social");  //check our connection… if (mysqli_connect_errno($con)) {     echo " sorry mate"; } $username = $_post['username']; $password = $_post['pawd']; $result = mysqli_query($con, "select * user_info"); $row = mysqli_fetch_array($result); $value = $row['username']; if($value == "$username") {     $result = mysqli_query($con, "select * user_info username ='$username'");     $row = mysqli_fetch_array($result);     $value = $row['password'];     if($value == "$password")         {         $sql=("update user_check set user = '1', name = '$username'");         header( 'location: feed.php' ) ;         }         else         {         header( 'location: social.php' ) ;         } } else { header( 'location: social.php' ) ; } if (!mysqli_query($con,$sql))   {   die('error: ' . mysqli_error($con));   } mysqli_close($con); ?> 

which gets form data previous page not know why happening , have tryed changing php :

$result = mysqli_query($con, "select username user_info"); $row = mysqli_fetch_array($result); if($row == "$username") 

yet doesnt work either suggestions?

the problem that, after first query, info db, taking first row of table,

$row = mysqli_fetch_array($result);

then comparing submitted username, that's why can't login other username, solution add clause first query,

$result = mysqli_query($con, "select * user_info username ='".$username."'");

then compare passwords easier, still, there better ways authentication. example should do.