SQL · Theory

Split

Theory

390/439

Split

Don’t start Split with jargon. Start with Split on Arun's board. That is the whole point.

Split on the board — one Split step Arun can write from memory. Then say what Split on Arun's board looks like after.

Split exists so Arun can keep Split on Arun's board correct in lab hour.

Split shows up in lab hour. Name Split on Arun's board, not “a real-world scenario”.

Don’t do this with Split — copy-pasting Split without a dry-run. Interviewers spot it in ten seconds.

After Split, Arun should still remember copy-pasting Split without a dry-run.

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

Exam tip

Say Split in one breath, then one Split step Arun can write from memory, then copy-pasting Split without a dry-run.

Split — sample query

-- Split
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;

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

Short notes

DefSplit — Arun uses it for Split on Arun's board in lab hour.
RuleSplit → one Split step Arun can write from memory.
RememberSplit + InnoDB (lab hour).
UseSplit in lab hour (Split on Arun's board).
TrapSplit — copy-pasting Split without a dry-run.
ExSplit → Split on Arun's board.

-- Split 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;

Split

Split — sample query

Short notes

Questions

Split

Split — sample query

Short notes

Questions