SQL · Theory

Trim()()

Theory

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Trim()()

Don’t start Trim()() (str) with jargon. Start with Dev walking through Trim str. That is the whole point.

Trim()() (str) order: meaning → one Trim str step Dev can write from memory → one limit. Dumping ten features helps nobody.

Trim()() (str) exists so Dev can keep Dev walking through Trim str correct in lab hour.

Trim()() (str) shows up in lab hour. Name Dev walking through Trim str, not “a real-world scenario”.

If Dev walking through Trim str breaks under Trim()() (str), check skipping the failure case for Trim str first.

Trim()() (str) is not a lonely heading. Dev ties it to Dev walking through Trim str.

One breath for Trim()() (str), then Dev walking through Trim str, then skipping the failure case for Trim str. Sit down.

Exam tip

For Trim()() (str): definition + lab hour + one failure.

Trim()() — sample query

-- Trim()()
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;

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

Short notes

DefTrim()() (str) — Dev uses it for Dev walking through Trim str in lab hour.
RuleTrim()() (str) → one Trim str step Dev can write from memory.
RememberTrim()() (str) + the query planner (lab hour).
UseTrim()() (str) in lab hour (Dev walking through Trim str).
TrapTrim()() (str) — skipping the failure case for Trim str.
ExTrim()() (str) → Dev walking through Trim str.

-- Trim()() 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;

Trim()()

Trim()() — sample query

Short notes

Questions

Trim()()

Trim()() — sample query

Short notes

Questions