if (User::where('email', Input::get('email'))->exists()) {
// exists
}
// You may check for the existence of a table or column
// using the hasTable and hasColumn methods:
if (Schema::hasTable('users')) {
// The "users" table exists...
}
if (Schema::hasColumn('users', 'email')) {
// The "users" table exists and has an "email" column...
}