How do you use the ifnull function in Oracle?

Oracle does not provide a direct IFNULL function, but you can achieve similar functionality using the NVL function.

The syntax for the NVL function is as follows:

NVL(expr1, expr2)

Return the value of expr1 if it is not NULL, otherwise return the value of expr2.

For example, if you want to check if a field is NULL and display a specific value in the query results (such as displaying “Unknown”), you can use it like this:

SELECT NVL(column_name, 'Unknown') 
FROM table_name;

If the value of column_name is NULL, “Unknown” will be displayed in the query result.