DROP INDEX "user_group_memberships_user_group_uidx";--> statement-breakpoint
DELETE FROM "user_group_memberships"
WHERE ctid IN (
  SELECT ctid
  FROM (
    SELECT ctid, row_number() OVER (PARTITION BY "user_id" ORDER BY "created_at" DESC, "group_id") AS assignment_rank
    FROM "user_group_memberships"
  ) ranked_assignments
  WHERE assignment_rank > 1
);--> statement-breakpoint
CREATE UNIQUE INDEX "user_group_memberships_user_uidx" ON "user_group_memberships" USING btree ("user_id");