LN()() — SQL Technical Interview Questions & Answers

LN()()

LN()()

  • LN() is a MySQL math function: numeric function LN() — pass numbers, get a number. Use it in SELECT, e.g. SELECT LN(marks) FROM students;
  • These functions do not change stored marks unless you UPDATE. NULL in, NULL out for most of them.
  • Trap: mixing LN with TRUNCATE TABLE (different word). Trap: maths on VARCHAR without CAST.
  • In a viva, one numeric example beats listing twenty functions.
  • On the example next to this theory: LN()(): create two demo rows, then SELECT qty >= 2 ordered. Say which labels come back.

Technical Interview Tip: Explain LN with one number. numeric function LN() — pass numbers, get a number.

Code Examples for LN()()

LN()() — sample query

-- LN()()
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;

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

How to Explain LN()() to an Interviewer

What is LN?

numeric function LN() — pass numbers, get a number Used in SELECT