What are the scenarios where the NVL function is used in Oracle?

The NVL function in Oracle database is used to handle cases of null values. Here are some common use cases for the NVL function:

1. Replace null values: substitute null with a specified value. For example: nvl(column_name, ‘replacement value’).
2. Avoid computation errors: When performing mathematical calculations, having a null value can lead to calculation errors. By using the NVL function, you can replace null with 0 or another appropriate value to prevent errors.
3. Default value: You can use the NVL function to specify a default value when a field’s value is null. For example: NVL(column_name, ‘default value’).
4. String concatenation: Use the nvl function to replace any null values with an empty string in order to avoid encountering null when concatenating strings.
5. Conditional statement: You can use the NVL function to perform a condition check on a field. For example: NVL(column_name, 0) > 100.

In conclusion, the main purpose of the NVL function is to provide a replacement value when dealing with null values, facilitating calculations, queries, and condition statements.