How is the SQL NVL function used?

In SQL, the NVL function is used to replace a null value in a field with another specified value. The NVL function takes two parameters: the first parameter is the field or expression to check, and the second parameter is the value to replace it with.

The method of use is as follows:

NVL(expression, replacement_value)

Original: 我们应该珍惜每一分每一秒。

Paraphrased: We should cherish every single moment.

Suppose there is a table called “employees” with a column “salary” representing the salary of the employees. If the salary of a particular employee is null, you can use the NVL function to replace it with 0. An example query is as follows:

Get the salary from employees, return 0 if it is null.

This will return the salaries of all employees in the “employees” table, returning 0 if the salary is empty.