lumen validation: rule for value not exists in database

i´m using lumen 5.5 and want to prove that a given value is required, exists in table A and does NOT exist in table B.

while the first two rules can be found in the documentation I´m unable to find a solution for the third.

So this is what I currently use:

$rules = [
  'email' => 'required|exists:user,email'
];

Something like this is what I want:

$rules = [
  'email' => 'required|exists:user,email|not_exists:blocklist,email'
];

Someone know a simple validation rule for this?

Solution

Try this:

$rules = [
  'email' => 'required|exists:users|unique:blocklist'
];

Explanation:

With the exists rule we are making it sure that the provided email must exist in your users table under the column email.
With the unique rule we are making it sure that there must not exist a matching email in the blocklist table (under the email column).

In both cases, I didn't specify a column name because the attribute name is the same than the matching column in the database. If you want to customize it just include it after a ,. e.g: required|exists:users,another_column