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

GREATEST()()

GREATEST()()

  • GREATEST() is a MySQL math function: GREATEST(a,b,c) biggest argument. Use it in SELECT, e.g. SELECT GREATEST(marks) FROM students;
  • These functions do not change stored marks unless you UPDATE. NULL in, NULL out for most of them.
  • Trap: mixing GREATEST 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: GREATEST()(): create two demo rows, then SELECT qty >= 2 ordered. Say which labels come back.

Technical Interview Tip: Explain GREATEST with one number. GREATEST(a,b,c) biggest argument.

Code Examples for GREATEST()()

GREATEST()() — sample query

-- GREATEST()()
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;

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

How to Explain GREATEST()() to an Interviewer

What is GREATEST?

GREATEST(a,b,c) biggest argument Used in SELECT