[Solved] Given a table Products with columns price (nullable) and discount (nullable), what will this query return?SELECT COALESCE(discount, price, 0) AS final_price FROM Products; | SQL

SQL - CASE Expressions

Given a table Products with columns price (nullable) and discount (nullable), what will this query return?

SELECT COALESCE(discount, price, 0) AS final_price FROM Products;

AThe sum of discount and price or 0 if both are NULL

BAn error because COALESCE cannot have more than two arguments

COnly the discount value or 0 if discount is NULL

DThe first non-NULL value among discount, price, or 0 for each row

Step-by-Step Solution

Solution:

Step 1: Understand COALESCE evaluation order
COALESCE returns the first non-NULL value from left to right.
Step 2: Apply to given columns
It checks discount first, if NULL then price, if both NULL then 0.
Final Answer:
The first non-NULL value among discount, price, or 0 for each row -> Option D
Quick Check:
COALESCE returns first non-NULL value in order [OK]

Quick Trick: COALESCE checks values left to right, returns first non-NULL [OK]

Common Mistakes:

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