Username And Email Login Form Validation Question

Why? Because of performance.

I believe it's best practice to make as simple sql queries as possible. I you can get rid of a OR statement in your query with a few lines of php I believe it's woth it anytime.

Compare using

Code:

SELECT id,username,email,salt FROM users WHERE email='PostData' LIMIT 1

(Or if you determine 'PostData' is not a valid emailaddress)

Code:

SELECT id,username,email,salt FROM users WHERE username='PostData' LIMIT 1

To:

Code:

SELECT id,username,email,salt FROM users WHERE email='PostData' OR username='PostData' LIMIT 1