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SUBSTRING()()

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SUBSTRING()()

Don’t start SUBSTRING()() with jargon. Start with a SUBSTRING dry-run. That is the whole point.

For SUBSTRING()(), an index is in play. Don’t blame it until you have traced a SUBSTRING dry-run.

SUBSTRING()() exists so Kabir can keep a SUBSTRING dry-run correct in lab hour.

SUBSTRING()() shows up in lab hour. Name a SUBSTRING dry-run, not “a real-world scenario”.

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

Place SUBSTRING()() next to nearby SQL work — one SUBSTRING step Kabir can write from memory is the link.

Close SUBSTRING()() with: “If I skip it, a SUBSTRING dry-run goes wrong like this: copy-pasting SUBSTRING without a dry-run.”

Exam tip

For SUBSTRING()(): definition + lab hour + one failure.

SUBSTRING()() — sample query

-- SUBSTRING()()
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;

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

Short notes

DefSUBSTRING()() — Kabir uses it for a SUBSTRING dry-run in lab hour.
RuleSUBSTRING()() → one SUBSTRING step Kabir can write from memory.
RememberSUBSTRING()() + an index (lab hour).
UseSUBSTRING()() in lab hour (a SUBSTRING dry-run).
TrapSUBSTRING()() — copy-pasting SUBSTRING without a dry-run.
ExSUBSTRING()() → a SUBSTRING dry-run.

-- SUBSTRING()() 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;

SUBSTRING()()

SUBSTRING()() — sample query

Short notes

Questions

SUBSTRING()()

SUBSTRING()() — sample query

Short notes

Questions