ALTER GROUP name ADD USER username [, ... ] ALTER GROUP name DROP USER username [, ... ]
The name of the group to modify.
Users which are to be added or removed from the group. The user names must exist.
Message returned if the alteration was successful.
ALTER GROUP is used to change add users to a group or remove them from a group. Only database superusers can use this command. Adding a user to a group does not create the user. Similarly, removing a user from a group does not drop the user itself.
Use CREATE GROUP to create a new group and DROP GROUP to remove a group.
Add users to a group:
ALTER GROUP staff ADD USER karl, johnRemove a user from a group
ALTER GROUP workers DROP USER beth
There is no ALTER GROUP statement in SQL92. The concept of roles is similar.