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IF()

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IF()

Priya only reaches for IF() when a IF dry-run has to stay correct in a small live site.

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

Skip IF() and copy-pasting IF without a dry-run shows up in a small live site.

Use IF() when a IF dry-run must stay clear. If a simpler SQL step works, use that instead.

IF() miss — copy-pasting IF without a dry-run. Fix it before you talk about advanced SQL.

After IF(), Priya should still remember copy-pasting IF without a dry-run.

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

Exam tip

Board: a IF dry-run. Dry-run IF(). Name the trap: copy-pasting IF without a dry-run.

IF() — sample query

-- IF()
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;

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

Short notes

DefIF() — Priya uses it for a IF dry-run in a small live site.
RuleIF() → one IF step Priya can write from memory.
RememberIF() + an index (a small live site).
UseIF() in a small live site (a IF dry-run).
TrapIF() — copy-pasting IF without a dry-run.
ExIF() → a IF dry-run.

-- IF() 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;

IF()

IF() — sample query

Short notes

Questions

IF()

IF() — sample query

Short notes

Questions