Error:NO database is selected - php

Question

I tried it connection to database connection to database is successful but when i try to match user information with database it gives me a error NO database is selected
i tried it connecting to database using different method but nothing worked
<?php
//CREATING CONNECTION TO DATABASE
$con= new mysqli("localhost", "****", "***", "*****");
$con->select_db("lel_server_user_db_secured");
if(mysqli_connect_errno())
{
echo "Problem With connection to database Please contact administrator regarding this error";
}
/* RETURNS NAME OF DEFAULT DATABASE
if ($result = $con->query("SELECT DATABASE()")) {
$row = $result->fetch_row();
printf("Default database is %s.\n", $row[0]);
$result->close();
}
*/
/*
$host="localhost";
$db_user="sky.xpert";
$db_pass="havefun344";
$database="lel_server_user_db_secured";
mysqli_connect($host,$db_user,$db_pass,$database) or die ("Failed to connect");
mysqli_select_db($database) ;
*/
session_start();
//GATHERING DATA FROM USER FORM
$email=$_POST["login"];
$pass=$_POST["pwd"];
//COMMANDING WHERE TO FIND MATCH FOR LGOIN INFORMATION
$veryfy="SELECT * FROM users WHERE Email='$email' Password='$pass'";
$query=mysql_query($veryfy) or die ( mysql_error() );
$match=0;
$match=mysql_num_rows($query);
//IF MATCH FOUND THEN SETTING SESSION AND REDIRECTING IT TO LOGGED PAGE
if($match==1)
{
$_SESSION['loggedin'] = "true";
header ("Location: logged.php"); //REDIRECTING USER TO ITS HOMEPAGE
}
else //IF MATCH NOT FOUND THEN REDIRECTING IT BACK TO LOGIN PAGE
{
$_SESSION['loggedin'] = "false";
header ("Location: index.php");
}
//PERSONAL COMMENTS OR DETIALED COMMENTS
//PROBLEM WITH THIS SCRIPT GIVING OUTPUT ON LOGIN "NO DATABASE SELECTED"
//REFRENCE from http://www.dreamincode.net/forums/topic/52783-basic-login-script-with-php/
?>

Answer 1

You are initializing a connection to your database with mysqli. Then you try to do queries with mysql. Obviously, there is no connection with the database made through that library, and therefore it fails with an error. Change mysql_query to mysqli_query.
General note
Your current code is vulnerable to sql injection attacks, because you do not sanitize the input from the user before putting it in a query. Consider using prepared queries.

Answer 2

The database lel_server_user_db_secured may be not exist.
Content to your mysql:
mysql -hlocalhost -uusername -p
then input your password. After login, type command:
show databases;
check if lel_server_user_db_secured is in the result.
update1*
change the code below:
$veryfy="SELECT * FROM users WHERE Email='$email' Password='$pass'";
$query=mysql_query($veryfy) or die ( mysql_error() );
$match=0;
$match=mysql_num_rows($query);
to:
$veryfy="SELECT * FROM users WHERE Email='$email' Password='$pass'";
$result = mysqli_query($con, $veryfy) or die ( mysqli_connect_errno() );
$match=0;
$match=mysqli_num_rows($result);
var_dump($match);

Answer 3

In the first half of your program you have used mysqli and in the latter half mysql. Either use mysqli or mysql. I would recommend using mysqli in your entire program so that you are not vulnerable to SQL injection

Answer 4

you can simply do it by
$mysqli = new mysqli("localhost", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
there is no need to do $con->select_db("lel_server_user_db_secured"); again
and using mysqli isnt mean your code is safe ... your code is still vulnerable to SQL injection Use prepared statement instead or atleast mysqli_real_escape_string
You need to escape all request properly
and its possible that your database isnt exist so check that its exist first
AND you are mixing tow different API
you can not use MySQLi functions with MySQL_* function