ReferenceBeginner15 min read
12. Timeline, tools & cheat sheet
SQL · 48 pages source format
Return when stuck. Week map, safety ritual, and interview quick hits.
What you'll learn
- 10-week map
- Safety ritual
- Interview one-liners
Week map
- Weeks 1–2 — SELECT, WHERE, ORDER BY
- Weeks 3–4 — JOINs + Checkpoint A
- Weeks 5–6 — GROUP BY, subqueries, CTEs
- Weeks 7–8 — mutations, transactions
- Weeks 9–10 — indexes, EXPLAIN + Checkpoint B
Clear?
Safety ritual (always)
SELECT with same WHERE → count rows → BEGIN → mutate → verify → COMMIT or ROLLBACK.
Do this now
Pin SAFETY.md. Never UPDATE/DELETE without WHERE in production.
Clear?
Interview one-liners
JOIN: match rows on keys. GROUP BY: aggregate grain. HAVING: filter groups. Index: speeds reads, costs writes. Transaction: all-or-nothing.
Do this now
Maintain docs/sql-interview.md in sql-notes repo.
Clear?
