Hello Andy and others - On Sun, Apr 2, 2017 at 5:13 PM, Andy Colson <a...@squeakycode.net> wrote:
> On 04/02/2017 09:26 AM, Alexander Farber wrote: >> >> http://stackoverflow.com/questions/43168406/merging-records- >> in-a-table-with-2-columns-primary-key > > after some thinking, when I call SELECT out_uid FROM merge_users(ARRAY[1,2,3,4]); then "reviews" table should be empty (get rid of all self-reviews) and "users" should contain just 1 record (1, 'User 1'). And if instead I call SELECT out_uid FROM merge_users(ARRAY[1,2]); then "reviews" should be (records with User 2 removed because overlapped with User 1): uid | author | review -----+--------+------------------------ 1 | 3 | User 3 says: 1 is nice 1 | 4 | User 4 says: 1 is nice 3 | 1 | User 1 says: 3 is nice 3 | 4 | User 4 says: 3 is ugly 4 | 1 | User 1 says: 4 is ugly 4 | 3 | User 3 says: 4 is ugly and "users": uid | name -----+-------- 1 | User 1 3 | User 3 4 | User 4 So my 2 questions are - 1) Why the error when calling merge_users(ARRAY[1,2]) and then merge_users(ARRAY[1,2,3,4])? 2) Is there a way to use an UPDATE reviews instead of the inefficient (because copying) INSERT ... SELECT ... ON CONFLICT DO NOTHING? Thank you Alex
