SQL Essentials: NVL vs COALESCE

Overview

NVL and COALESCE are both SQL functions used to handle and replace null values in a dataset, but they have distinct characteristics and use cases.

NVL Function:

• Definition: NVL is a function that replaces null values with an alternative value, ensuring that the result is never null.
  
• Syntax: NVL(expression, replacement)
  
• Result: It evaluates the 'expression' and if it is null, it returns the 'replacement' value. If the 'expression' is not null, it returns the original value.
  
• Use Case: NVL is ideal for situations where you want to ensure that a specific field or calculation always has a value, even if the original data is missing or null.