SQL

login to mysql

mysql -u USERNAME -p

login to mysql database

mysql -u root -p databasename

MYSQL LOGIN

$result = mysql_query("SELECT COUNT(*) 
    FROM `users_tbl` 
    WHERE `userName` = '$name' AND `password` = '$pass'");

if (!$result || mysql_num_rows($result) <= 0) {
    // NO user found!
} else {
    // User found and password matches
}