CiviCRM Community Forums (archive)

The "View Contacts" link for group id 92 for a CiviCRM 4.2.6 site is:

INSERT IGNORE INTO civicrm_group_contact_cache (group_id,contact_id) (
SELECT 92 as group_id, contact_id as id
FROM   civicrm_group_contact
WHERE  civicrm_group_contact.status = 'Added'
  AND  civicrm_group_contact.group_id = 92 );
but it fails with

Cannot add or update a child row: a foreign key constraint fails (`civicrm_group_contact_cache`, CONSTRAINT `FK_civicrm_group_contact_cache_contact_id` FOREIGN KEY (`contact_id`) REFERENCES `civicrm_contact` (`id`) ON DELETE CASCADE)]

What is the reason it fails? Because the SELECT brings up a set of non-existent contacts. I made this SQL to test:

SELECT 92 as group_id, contact_id as id
FROM   civicrm_group_contact
LEFT JOIN   civicrm_contact cc on cc.id = civicrm_group_contact.contact_id
WHERE  civicrm_group_contact.status = 'Added'
  AND  civicrm_group_contact.group_id = 92
  and cc.id is null;
and it finds 35 rows in civicrm_group_contact where the contact_id doesn't exist in civicrm_contact.

I can remove those 35 rows but I am wondering how they got there....