Delete Duplicate Records — SQL Technical Interview Questions & Answers

Delete Duplicate Records

Delete Duplicate Records

  • Delete Duplicate Records is a MySQL topic you learn with one small college example — a students table with roll, name, marks. Say what Delete Duplicate Records does in one sentence, then write the shortest SQL that shows it.
  • Pattern: USE college; then a CREATE/SELECT/UPDATE that needs Delete Duplicate Records. If it is a function, SELECT it on one column. If it is DDL, run SHOW / DESCRIBE after so you can see the change.
  • Trap: only reciting the heading Delete Duplicate Records with no SQL. Interviewers ask you to type. Another trap: mixing this up with a neighbouring command (DELETE vs TRUNCATE vs DROP, WHERE vs HAVING, JOIN vs UNION).
  • Keep the example on paper: two or three rows. Change one value. Predict the result before you run it.
  • On the example next to this theory: Delete Duplicate Records — dELETE removes matching rows. TRUNCATE clears a whole table faster (MySQL).

Technical Interview Tip: What is Delete Duplicate Records? One sentence + one tiny SQL on students.

Code Examples for Delete Duplicate Records

Delete Duplicate Records — sample query

CREATE TABLE tags (id INTEGER PRIMARY KEY, label TEXT);
INSERT INTO tags VALUES (1, 'old'), (2, 'keep');
DELETE FROM tags WHERE label = 'old';
SELECT * FROM tags;

Delete Duplicate Records — dELETE removes matching rows. TRUNCATE clears a whole table faster (MySQL).

How to Explain Delete Duplicate Records to an Interviewer

What is Delete Duplicate Records?

A MySQL idea used with tables/queries Show one short SQL

Give an example.

students table SQL that uses Delete Duplicate Records

What mistake do beginners make?

Name only, no SQL Mixing nearby commands