AFTER UPDATE Trigger — SQL Technical Interview Questions & Answers

AFTER UPDATE Trigger

AFTER UPDATE Trigger

  • AFTER UPDATE Trigger (AFTER_UPDATE_TRIGGER) is a MySQL date/time helper. Dates are stored in DATE / DATETIME / TIMESTAMP columns. Always quote literals: '2026-08-19'.
  • Typical pattern: SELECT AFTER_UPDATE_TRIGGER(…); or SELECT AFTER_UPDATE_TRIGGER(dob) FROM students; NOW() / CURDATE() / CURTIME() have empty brackets — they read the clock.
  • DATE_FORMAT(dob, '%d-%b-%Y') is for display. DATEDIFF(end, start) is days between. INTERVAL 7 DAY is how you add a week: DATE_ADD(CURDATE(), INTERVAL 7 DAY).
  • Trap: comparing dates as VARCHAR. Trap: TIMESTAMP vs DATETIME timezone stories — DATETIME is ‘wall clock’, TIMESTAMP is UTC-stored (say this only if asked).
  • On the example next to this theory: AFTER UPDATE Trigger — uPDATE changes existing rows — always scope with WHERE.

Technical Interview Tip: AFTER_UPDATE_TRIGGER: one SELECT example. Quote 'YYYY-MM-DD'.

Code Examples for AFTER UPDATE Trigger

AFTER UPDATE Trigger — sample query

CREATE TABLE products (id INTEGER PRIMARY KEY, name TEXT, price REAL);
INSERT INTO products VALUES (1, 'Mouse', 499);
UPDATE products SET price = 449 WHERE id = 1;
SELECT * FROM products;

AFTER UPDATE Trigger — uPDATE changes existing rows — always scope with WHERE.

How to Explain AFTER UPDATE Trigger to an Interviewer

What is AFTER_UPDATE_TRIGGER?

Date/time function for AFTER UPDATE Trigger Use in SELECT on a DATE column

Current datetime?

NOW() or CURRENT_TIMESTAMP