SQL · Theory

ROLLUP

Theory

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ROLLUP

ROLLUP is a SQL idea you prove with ROLLUP on Arun's board, not with a slogan.

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

ROLLUP exists so Arun can keep ROLLUP on Arun's board correct in a viva board.

Arun ships ROLLUP in a viva board. That is the use case worth saying.

If ROLLUP on Arun's board breaks under ROLLUP, check copy-pasting ROLLUP without a dry-run first.

ROLLUP is not a lonely heading. Arun ties it to ROLLUP on Arun's board.

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

Exam tip

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

ROLLUP — sample query

-- ROLLUP
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;

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

Short notes

DefROLLUP — Arun uses it for ROLLUP on Arun's board in a viva board.
RuleROLLUP → one ROLLUP step Arun can write from memory.
RememberROLLUP + an index (a viva board).
UseROLLUP in a viva board (ROLLUP on Arun's board).
TrapROLLUP — copy-pasting ROLLUP without a dry-run.
ExROLLUP → ROLLUP on Arun's board.

-- ROLLUP 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;

ROLLUP

ROLLUP — sample query

Short notes

Questions

ROLLUP

ROLLUP — sample query

Short notes

Questions