NVL` and `IFNULL` are two functions in Snowflake that serve the same purpose: replacing NULL values with a specified replacement value. While their syntax is identical, there are some subtle differences between them. `NVL` comes from Oracle's SQL dialect, while `IFNULL` originates from MySQL. In terms of performance, both functions are optimized equally well by the query engine. However, `IFNULL` is more readable and clearly describes its purpose, making it a better choice for self-documenting code. On the other hand, `NVL` might be preferred in Oracle migration projects or when working with existing codebases that already use `NVL`. Ultimately, the decision between `NVL` and `IFNULL` should be based on consistency across the codebase, team background, and readability preferences. Additionally, Snowflake offers additional NULL-handling functions like `COALESCE`, `NULLIF`, and `ZEROIFNULL` that can be used to handle various scenarios. By mastering these functions, developers can effectively address NULL values in their data and ensure accurate analytics and decision-making.