Temporary Table — SQL Technical Interview Questions & Answers

Temporary Table

Temporary Table

  • CREATE TEMPORARY TABLE tmp_fail AS SELECT * FROM students WHERE marks < 40; lives only for this connection. When you disconnect, it disappears. Other users cannot see it.
  • Use it for a messy report: filter, join, then SELECT from tmp. Don’t confuse with a normal table of the same name — TEMPORARY hides the real one in that session.
  • Trap: expecting a temporary table to still be there tomorrow.
  • On the example next to this theory: Temporary Table: create two demo rows, then SELECT qty >= 2 ordered. Say which labels come back.

Technical Interview Tip: CREATE TEMPORARY TABLE … — gone when the session ends.

Code Examples for Temporary Table

Temporary Table — sample query

-- Temporary 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;

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

How to Explain Temporary Table to an Interviewer

Who can see a TEMPORARY table?

Only this connection Dropped on disconnect