PostgreSQL - Triggers in PostgreSQL
In a BEFORE UPDATE trigger, what does the following PL/pgSQL statement evaluate to?
RETURN NEW.price > OLD.price;
In a BEFORE UPDATE trigger, what does the following PL/pgSQL statement evaluate to?
medium📝 query result Q4 of 15
Step-by-Step Solution
Solution:
Step 1: Understand the RETURN statement
The statement returns a boolean result of the comparison between NEW.price and OLD.price.Step 2: Evaluate the expression
NEW.price > OLD.price returns TRUE if the new price is greater than the old price, otherwise FALSE.Final Answer:
Returns TRUE if the new price is greater than the old price -> Option DQuick Check:
Boolean comparison returns TRUE/FALSE [OK]
Quick Trick: RETURN with comparison returns boolean result [OK]
Common Mistakes:
- Assuming RETURN returns a record instead of boolean
- Confusing NEW and OLD record references
- Thinking it causes an error
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