TECH TIP - If the above SQL statement fails with error - 'ora-01489 result of string concatenation is too long' you can potentially resolve by adding the desired group type to the where clause.
Typically this is a one of the Business Service groups or a custom group. Find this WHERE in the SQL and add an AND with the type of group you are looking to delete.
WHERE a.entity_type = b.entity_type_id
AND b.entity_class = 'group'
-- Add in line below, replacing 'group_type' with desired type. Example 'business_service'
AND b.entity_type = 'group_type'