NULLS FIRST / NULLS LAST

-- Sort ascending, putting NULLs at the bottom
SELECT name, deleted_at
FROM   users
ORDER  BY deleted_at ASC NULLS LAST;

-- Most-recently-updated first; "never updated" at the end
SELECT id, title, updated_at
FROM   posts
ORDER  BY updated_at DESC NULLS LAST;

-- MySQL doesn't support NULLS FIRST/LAST directly — emulate:
SELECT * FROM posts ORDER BY (updated_at IS NULL), updated_at DESC;
--                          ↑ 0 first (non-null), then 1 (null)

-- Use in window functions too
SELECT id, score,
       RANK() OVER (ORDER BY score DESC NULLS LAST) AS rank
FROM   players;