Hello Andy and others -
On Sun, Apr 2, 2017 at 5:13 PM, Andy Colson <andy@xxxxxxxxxxxxxxx> 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
