SQL · Theory

Regular Expressions

Theory

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Regular Expressions

If you can teach Regular Expressions using Regular Expressions on Meera's board, you know it. If you only know the heading, you don’t.

Do Regular Expressions once by hand. one Regular Expressions step Meera can write from memory. Change one input. Say the new result out loud.

Without Regular Expressions, a campus project gets messy and Regular Expressions on Meera's board is hard to trust.

Meera ships Regular Expressions in a campus project. That is the use case worth saying.

Don’t do this with Regular Expressions: copy-pasting Regular Expressions without a dry-run. Interviewers spot it in ten seconds.

Regular Expressions is not a lonely heading. Meera ties it to Regular Expressions on Meera's board.

One breath for Regular Expressions, then Regular Expressions on Meera's board, then copy-pasting Regular Expressions without a dry-run. Sit down.

Exam tip

Say Regular Expressions in one breath, then one Regular Expressions step Meera can write from memory, then copy-pasting Regular Expressions without a dry-run.

Regular Expressions — sample query

-- Regular Expressions
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;

Regular Expressions: create two demo rows, then SELECT qty >= 2 ordered. Say which labels come back.

Short notes

DefRegular Expressions — Meera uses it for Regular Expressions on Meera's board in a campus project.
RuleRegular Expressions → one Regular Expressions step Meera can write from memory.
RememberRegular Expressions + InnoDB (a campus project).
UseRegular Expressions in a campus project (Regular Expressions on Meera's board).
TrapRegular Expressions — copy-pasting Regular Expressions without a dry-run.
ExRegular Expressions → Regular Expressions on Meera's board.

-- Regular Expressions 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;

Regular Expressions

Regular Expressions — sample query

Short notes

Questions

Regular Expressions

Regular Expressions — sample query

Short notes

Questions