Fix #4619 SELECT LENGTH(`field`) FROM  does not sort

Signed-off-by: Hugues Peccatte <hugues.peccatte@gmail.com>
Update ChangeLog.

Signed-off-by: Hugues Peccatte <hugues.peccatte@gmail.com>
Fix merge conflict

Signed-off-by: Marc Delisle <marc@infomarc.info>