SQL · Theory

8.0

← All stacks

Theory

375/439

8.0

8.0 (mysql) sits in a viva board. Dev’s job is Dev walking through 8.0 mysql. Write that first.

Keep 8.0 (mysql) small. Dev should finish Dev walking through 8.0 mysql in a few lines, not a 40-line dump.

8.0 (mysql) exists so Dev can keep Dev walking through 8.0 mysql correct in a viva board.

8.0 (mysql) shows up in a viva board. Name Dev walking through 8.0 mysql, not “a real-world scenario”.

If Dev walking through 8.0 mysql breaks under 8.0 (mysql), check copy-pasting 8.0 mysql without a dry-run first.

8.0 (mysql) is not a lonely heading. Dev ties it to Dev walking through 8.0 mysql.

Viva for 8.0 (mysql): what it is → one 8.0 mysql step Dev can write from memory → the mistake (copy-pasting 8.0 mysql without a dry-run).

Exam tip

Board: Dev walking through 8.0 mysql. Dry-run 8.0 (mysql). Name the trap: copy-pasting 8.0 mysql without a dry-run.

8.0 — sample query

-- 8.0
CREATE TABLE demo (
  id INTEGER PRIMARY KEY,
  label TEXT NOT NULL,
  qty INTEGER DEFAULT 0
);
INSERT INTO demo (id, label, qty) VALUES
  (1, 'alpha', 2),
  (2, 'beta', 5);
SELECT label, qty FROM demo WHERE qty >= 2 ORDER BY qty DESC;

8.0: create two demo rows, then SELECT qty >= 2 ordered. Say which labels come back.

Short notes

Def8.0 (mysql) — Dev uses it for Dev walking through 8.0 mysql in a viva board.
Rule8.0 (mysql) → one 8.0 mysql step Dev can write from memory.
Remember8.0 (mysql) + the query planner (a viva board).
Use8.0 (mysql) in a viva board (Dev walking through 8.0 mysql).
Trap8.0 (mysql) — copy-pasting 8.0 mysql without a dry-run.
Ex8.0 (mysql) → Dev walking through 8.0 mysql.

-- 8.0 CREATE TABLE demo ( id INTEGER PRIMARY KEY, label TEXT NOT NULL, qty INTEGER DEFAULT 0 ); INSERT INTO demo (id, label, qty) VALUES (1, 'alpha', 2), (2, 'beta', 5); SELECT label, qty FROM demo WHERE qty >= 2 ORDER BY qty DESC;

8.0

8.0 — sample query

Short notes

Questions

8.0

8.0 — sample query

Short notes

Questions