Login in to website with php and MySQL

Question

On my website so far a user can add their username, password and email to a MySQL database through php. I want to now let a user type those same credentials (username and password) into forms and then run a php script and check if the Username and passwords are in the database. How would write this script?

Answer 1

Make a php function that gets what the user enters, then select them from your user table. If it returns something, say its is already in the database.

Example:

SELECT uname, pw FROM users WHERE uname="userNameInput" AND pw="userPwInput"; 

if this returns a row, it already is in the db.

You can then run this function on your choice of hitting a button or in every key stroke by calling the function with ajax.