How can I restore the data from a deleted Group

Question

Scenario is - contacts had been added to a Group (in this case for subsequent deletion) but a user then incorrectly deleted the Group, rather than the contacts in the Group.

Answer 1

Achieved this via SQL

Step 1. Identify contacts who the log_civicrm_group_contact table shows were added to the group (and who are not now in Trash, since we can add Trashed contacts to a Group) with a query that includes the value of the new group they will be added to (in this case 893) and filters for the Group that was deleted (764)

select 893, contact_id, log_civicrm_group_contact.status FROM log_civicrm_group_contact LEFT JOIN civicrm_contact cc ON cc.id = log_civicrm_group_contact.contact_id WHERE group_id = 764 AND status = "Added" AND log_action = "Insert" AND cc.is_deleted = 0 ORDER BY contact_id;

Then we grab the result as an SQL insert as follows

INSERT INTO civicrm_group_contact (group_id, contact_id, status) VALUES

with rows like

(893, 76639, 'Added')

Note we ORDERED by contact_id as we had too bit a sql insert so it got cut off, and by ordering by id we could rerun the insert scrip for those which got dropped from previous run.