[Solved] Which of the following best describes the behavior of the SQL function COALESCE? — Ans: Returns the first non-NULL value from a list of expressions | SQL

SQL - CASE Expressions

Which of the following best describes the behavior of the SQL function COALESCE?

AReturns NULL if all expressions are non-NULL

BReturns the first non-NULL value from a list of expressions

CReturns the last value in a list regardless of NULLs

DReturns the count of non-NULL values in a list

Step-by-Step Solution

Solution:

Step 1: Understand COALESCE
COALESCE evaluates its arguments in order and returns the first non-NULL value.
Step 2: Analyze options
Returns the first non-NULL value from a list of expressions correctly states this behavior. Options B, C, and D describe incorrect behaviors.
Final Answer:
Returns the first non-NULL value from a list of expressions -> Option B
Quick Check:
COALESCE(NULL, NULL, 5, 10) returns 5 [OK]

Quick Trick: COALESCE picks first non-NULL value [OK]

Common Mistakes:

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Which of the following best describes the behavior of the SQL function COALESCE?