PHP: Case-Insensitive Login Check
// simply logic:
if (username == usernameEntered && password == passwordEntered) {

if(strtolower(username) == strtolower(usernameEntered))

SELECT * FROM users WHERE LOWER(username) = LOWER(:username)

if (strtolower(username) == strtolower(usernameEntered) && strtolower(password) == strtolower(passwordEntered))

SELECT * FROM `users` WHERE `username` COLLATE utf8_general_ci = 'FoObAr'