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Ranking Functions

Theory

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Ranking Functions

If you can teach Ranking Functions using Ranking Functions on Meera's board, you know it. If you only know the heading, you don’t.

Ranking Functions order: meaning → one Ranking Functions step Meera can write from memory → one limit. Dumping ten features helps nobody.

Ranking Functions exists so Meera can keep Ranking Functions on Meera's board correct in lab hour.

Use Ranking Functions when Ranking Functions on Meera's board must stay clear. If a simpler SQL step works, use that instead.

Ranking Functions trap — only reciting the name of Ranking Functions. Meera loses marks for that every viva.

Place Ranking Functions next to nearby SQL work — one Ranking Functions step Meera can write from memory is the link.

Viva for Ranking Functions: what it is → one Ranking Functions step Meera can write from memory → the mistake (only reciting the name of Ranking Functions).

Exam tip

For Ranking Functions: definition + lab hour + one failure.

Ranking Functions — sample query

-- Ranking Functions
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;

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

Short notes

DefRanking Functions — Meera uses it for Ranking Functions on Meera's board in lab hour.
RuleRanking Functions → one Ranking Functions step Meera can write from memory.
RememberRanking Functions + InnoDB (lab hour).
UseRanking Functions in lab hour (Ranking Functions on Meera's board).
TrapRanking Functions — only reciting the name of Ranking Functions.
ExRanking Functions → Ranking Functions on Meera's board.

-- Ranking Functions 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;

Ranking Functions

Ranking Functions — sample query

Short notes

Questions

Ranking Functions

Ranking Functions — sample query

Short notes

Questions