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Subdate()

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Subdate()

Sara only reaches for Subdate() when a Subdate dry-run has to stay correct in a viva board.

Keep Subdate() small. Sara should finish a Subdate dry-run in a few lines, not a 40-line dump.

Without Subdate(), a viva board gets messy and a Subdate dry-run is hard to trust.

Subdate() shows up in a viva board. Name a Subdate dry-run, not “a real-world scenario”.

If a Subdate dry-run breaks under Subdate(), check skipping the failure case for Subdate first.

Subdate() is not a lonely heading. Sara ties it to a Subdate dry-run.

Close Subdate() with — “If I skip it, a Subdate dry-run goes wrong like this: skipping the failure case for Subdate.”

Exam tip

For Subdate(): definition + a viva board + one failure.

Subdate() — sample query

-- Subdate()
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;

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

Short notes

DefSubdate() — Sara uses it for a Subdate dry-run in a viva board.
RuleSubdate() → one Subdate step Sara can write from memory.
RememberSubdate() + InnoDB (a viva board).
UseSubdate() in a viva board (a Subdate dry-run).
TrapSubdate() — skipping the failure case for Subdate.
ExSubdate() → a Subdate dry-run.

-- Subdate() 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;

Subdate()

Subdate() — sample query

Short notes

Questions

Subdate()

Subdate() — sample query

Short notes

Questions