The docs for L4.2 show examples of how to use exists with values for a 'where' clause when checking a database table but there's no example that shows the same thing using the actual value submitted.
The below snippet is from the docs (http://laravel.com/docs/4.2/validation#rule-exists)
// You may also specify more conditions that will be added as "where" clauses to the query: 'email' => 'exists:staff,email,account_id,1'
Using the example above, how would I check the email value submitted exists in the table? The following doesn't work.
'email' => 'exists:staff,email,email,:attribute'