Example: 1


	<?php

	$username = $_POST['username'];
	$password = $_POST['password'];

	if($username && $password)
	{

	$connect = mysql_connect("localhost","root","admin") or die("Couldn't connect!");
	mysql_select_db("phplogin") or die("Couldn't find db");

	$query= mysql_query("SELECT * From users WHERE username='$username'");
	$numrows = mysql_num_rows($query);

	}
	else
   	die("Please enter  username and Password!");

	?>

	
Example: 2


	<?php

	$username = $_POST['username'];
	$password = $_POST['password'];

	if($username && $password)
	{

	$connect = mysql_connect("localhost","root","admin") or die("Couldn't connect!");
	mysql_select_db("phplogin") or die("Couldn't find db");

	$query= mysql_query("SELECT * From users WHERE username='$username'");
	$numrows = mysql_num_rows($query);

	echo $numrows;
	}
	else
 	  die("Please enter  username and Password!");

	?>



Example 3



	<?php

	$username = $_POST['username'];
	$password = $_POST['password'];

	if($username && $password)
	{

	$connect = mysql_connect("localhost","root","admin") or die("Couldn't connect!");
	mysql_select_db("phplogin") or die("Couldn't find db");

	$query= mysql_query("SELECT * From users WHERE username='$username'");
	$numrows = mysql_num_rows($query);

	if ($numrows!=0)
	{
	//code to login
	 while ($row = mysql_fetch_assoc($query))
	 	{
			$dbusername = $row['username'];
			$dbpassword = $row['password'];
		}
		if($username==$dbusername&&$password==$dbpassword)
		{
			echo "You're in!";
		}
		else
		 echo "Incorrect password!";
		
	}
	else
	die("That user does't exist!");

	
	}
	else
   	die("Please enter  username and Password!");

	?>


Example 4


	<?php

	$username = $_POST['username'];
	$password = $_POST['password'];

	if($username && $password)
	{

	$connect = mysql_connect("localhost","root","admin") or die("Couldn't connect!");
	mysql_select_db("phplogin") or die("Couldn't find db");

	$query= mysql_query("SELECT * From users WHERE username='$username'");
	$numrows = mysql_num_rows($query);

	if ($numrows!=0)
	{
	//code to login
	 while ($row = mysql_fetch_assoc($query))
	 	{
			$dbusername = $row['username'];
			$dbpassword = $row['password'];
		}
		if($username==$dbusername&&$password==$dbpassword)
		{
			echo "You're in!";
		}
		else
		 echo "Incorrect password!";
		
	}
	else
	die("That user does't exist!");

	
	}
	else
 	  die("Please enter  username and Password!");

	?>


Example 5



	<html>

	<form action='login5.php' method='POST'>
		Username: <input type='text' name='username'><br>
		Password: <input type='password' name='password'><br>
		<input type='submit' name='Log in'>
	</form>

	</html>

