SQL · Theory

FLOOR()()

Theory

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FLOOR()()

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

Do FLOOR()() (math) once by hand. one FLOOR math step Dev can write from memory. Change one input. Say the new result out loud.

Without FLOOR()() (math), a first job task gets messy and Dev walking through FLOOR math is hard to trust.

Use FLOOR()() (math) when Dev walking through FLOOR math must stay clear. If a simpler SQL step works, use that instead.

Don’t do this with FLOOR()() (math) — skipping the failure case for FLOOR math. Interviewers spot it in ten seconds.

After FLOOR()() (math), Dev should still remember skipping the failure case for FLOOR math.

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

Exam tip

For FLOOR()() (math): definition + a first job task + one failure.

FLOOR()() — sample query

-- FLOOR()()
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;

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

Short notes

DefFLOOR()() (math) — Dev uses it for Dev walking through FLOOR math in a first job task.
RuleFLOOR()() (math) → one FLOOR math step Dev can write from memory.
RememberFLOOR()() (math) + an index (a first job task).
UseFLOOR()() (math) in a first job task (Dev walking through FLOOR math).
TrapFLOOR()() (math) — skipping the failure case for FLOOR math.
ExFLOOR()() (math) → Dev walking through FLOOR math.

-- FLOOR()() 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;

FLOOR()()

FLOOR()() — sample query

Short notes

Questions

FLOOR()()

FLOOR()() — sample query

Short notes

Questions