FQL:group_member

official docs

Query this table to return information about the members of a group.

Note: This method may not return a complete list if there are a lot of results.

Columns

Highlighted rows are indexable / searchable and one is usually required in the WHERE portion of the query.

Name	Type	Description
uid	int	The user ID of the member of the group being queried.
gid	int	The ID of the group being queried.
positions	array	A list of positions taken by the member of the group being queried.
administrator	boolean	Returns true if the user is an administrator of the group.
bookmark_order	int	The order in which the group appears in the user's list of groups. This field requires the user_groups permission, and is only present when you query by uid. (returns null when proper permission isn't obtained)
unread	int	A count of items in this group which have not been read by the user. This field requires the user_groups permission, and is only present when you query by uid. (appears to be a value from 0-25 or 1 if permission isn't obtained)