Oracle ISNULL? Use NVL Instead

In Oracle, unlike other database systems such as SQL Server, there is no ISNULL function, instead, the NVL function is used to achieve similar functionality.

The syntax of the NVL function is as follows: NVL(expr1, expr2)

This function takes two parameters. If expr1 is not NULL, it returns the value of expr1; if expr1 is NULL, it returns the value of expr2.

For example, suppose there is a table called person with a field named name, you can use the NVL function to handle NULL values. Here is an example query:
SELECT NVL(name,’Unknown’) FROM person;

The above query will return the value of the name field, and if the name field is NULL, it will return the string ‘Unknown’.