[Solved] Why does this trigger fail to log updates? CREATE TRIGGER audit_update AFTER UPDATE ON customers FOR EACH ROW BEGIN INSERT INTO audit_log(customer_id,... Why does this trigger fail to log updates? | SQL

SQL - Triggers

Why does this trigger fail to log updates? CREATE TRIGGER audit_update AFTER UPDATE ON customers FOR EACH ROW BEGIN INSERT INTO audit_log(customer_id, action_time) VALUES (OLD.id, CURRENT_TIMESTAMP); END;

AIt uses OLD.id instead of NEW.id to log updated data

BAFTER UPDATE triggers cannot insert into other tables

CCURRENT_TIMESTAMP is not allowed in triggers

DFOR EACH ROW is missing in the trigger definition

Step-by-Step Solution

Solution:

Step 1: Understand NEW vs OLD in UPDATE triggers
NEW contains the new row data after update; OLD contains old data before update.
Step 2: Identify correct value to log
To log updated data, NEW.id should be used, not OLD.id.
Final Answer:
It uses OLD.id instead of NEW.id to log updated data -> Option A
Quick Check:
Use NEW.id to log updated rows in AFTER UPDATE triggers = It uses OLD.id instead of NEW.id to log updated data [OK]

Quick Trick: Use NEW for updated values, OLD for deleted or old values [OK]

Common Mistakes:

Using OLD.id to log updated data
Assuming triggers cannot insert data
Missing FOR EACH ROW clause

Master "Triggers" in SQL

9 interactive learning modes - each teaches the same concept differently

Learn Why Deep Visual Try Challenge Project Recall Time

More SQL Quizzes

Why does this trigger fail to log updates?

Step 1: Understand NEW vs OLD in UPDATE triggers

Step 2: Identify correct value to log

Final Answer:

Quick Check:

Want More Practice?