src/IdentityModel.php
public function existEmail(string $email): int
    {
        return (int) $this->connection->select(self::COLUMN_ID)
            ->from($this->tableIdentity)
            ->where(['email' => $email])
            ->fetchSingle();
    }
public function existEmail(string $email): int
    {
        return (int) $this->connection->select(self::COLUMN_ID)
            ->from($this->tableIdentity)
            ->where(['email' => $email])
            ->fetchSingle();
    }
Exist email.

@param string $email
@return int