Describe Table — SQL Technical Interview Questions & Answers

Describe Table

Describe Table

  • DESCRIBE students; or DESC students; prints columns, types, NULL, key, default. Same idea: SHOW COLUMNS FROM students; or SHOW CREATE TABLE students; (full CREATE text including keys).
  • Use this when you forgot whether marks is INT or VARCHAR. Don’t guess types in an interview — DESCRIBE.
  • Trap: DESCRIBE on a view still works, but you won’t see indexes the same way as a base table.
  • On the example next to this theory: Describe Table: create two demo rows, then SELECT qty >= 2 ordered. Say which labels come back.

Technical Interview Tip: DESC students; and SHOW CREATE TABLE students;

Code Examples for Describe Table

Describe Table — sample query

-- Describe Table
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;

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

How to Explain Describe Table to an Interviewer

How do you see column types?

DESCRIBE students; SHOW CREATE TABLE students;