How can I check if a user's email exists in the database

Question

When making a registration and saving information in the database I want to check if the user's email has already been registrated.

function user_id_exists($user){
    global $wpdb;

    $count = $wpdb->get_var($wpdb->prepare("SELECT COUNT(*) FROM $wpdb->users WHERE ID = %d", $user));

    if($count == 1){ return true; }else{ return false; }
}

It should be something like this

Answer 1

There's the email_exists() function that could help you with checking if an email already exists among users.

It's e.g. used by register_new_user().

More here:

https://developer.wordpress.org/reference/functions/email_exists/

https://developer.wordpress.org/reference/functions/register_new_user/