Pseudonymization replaces direct identifiers with a pseudonym, for example a salted hash; the data remains personal because a separate table or key makes re-identification possible. Anonymization, which is irreversible, no longer allows a person to be identified and takes the data out of the scope of the GDPR, but it is hard to guarantee.
Example
SHA2(CONCAT(email, :sel), 256) AS id_pseudonyme