Missing nids from node table

missing_node_ids.sql

SELECT (t1.nid + 1) as gap_starts_at,
       (SELECT MIN(t3.nid) -1 FROM node t3 WHERE t3.nid > t1.nid) as gap_ends_at 
FROM node t1
  WHERE NOT EXISTS (SELECT t2.nid FROM node t2 WHERE t2.nid = t1.nid + 1) 
  HAVING gap_ends_at IS NOT NULL

For users

SELECT (t1.uid + 1) as gap_starts_at,
(SELECT MIN(t3.uid) -1 FROM users t3 WHERE t3.uid > t1.uid) as gap_ends_at
FROM users t1
WHERE NOT EXISTS (SELECT t2.uid FROM users t2 WHERE t2.uid = t1.uid + 1)
HAVING gap_ends_at IS NOT NULL