SQL · Theory

MID()()

Theory

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MID()()

MID()() (str) is a SQL idea you prove with a MID str dry-run, not with a slogan.

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

MID()() (str) exists so Dev can keep a MID str dry-run correct in a campus project.

Dev ships MID()() (str) in a campus project. That is the use case worth saying.

Don’t do this with MID()() (str) — only reciting the name of MID str. Interviewers spot it in ten seconds.

MID()() (str) is not a lonely heading. Dev ties it to a MID str dry-run.

Close MID()() (str) with — “If I skip it, a MID str dry-run goes wrong like this: only reciting the name of MID str.”

Exam tip

For MID()() (str): definition + a campus project + one failure.

MID()() — sample query

-- MID()()
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;

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

Short notes

DefMID()() (str) — Dev uses it for a MID str dry-run in a campus project.
RuleMID()() (str) → one MID str step Dev can write from memory.
RememberMID()() (str) + the query planner (a campus project).
UseMID()() (str) in a campus project (a MID str dry-run).
TrapMID()() (str) — only reciting the name of MID str.
ExMID()() (str) → a MID str dry-run.

-- MID()() 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;

MID()()

MID()() — sample query

Short notes

Questions

MID()()

MID()() — sample query

Short notes

Questions