fcn_fudforums=# UPDATE fud26_1_read SET user_id=4, thread_id=t.id, msg_id=t.last_post_id, last_view=1085673943 FROM (SELECT id, last_post_id FROM fud26_1_thread WHERE forum_id=4) t WHERE user_id=4;
ERROR:  Cannot insert a duplicate key into unique index fud26_1_read_i_tu
fcn_fudforums=# UPDATE fud26_1_read SET user_id=4, thread_id=t.id, msg_id=t.last_post_id, last_view=1085673943 FROM (SELECT id, last_post_id FROM fud26_1_thread WHERE forum_id=4) t WHERE user_id=4 AND thread_id=t.id;
UPDATE 6