What is the use of using null function.... In sql?

Question

usage of null function

Answer 1

select name, lastname, phone
from addressbook
where phone is null

Answer 2

you can use it in your query to find empty records
of you can make records default null to avoid of wrong info

Answer 3

NULL is used to filter out missing values from the table.

A scenario wherein you're supposed to get a report generated of the list of people whose last name is not null can be written as:

SELECT fname, lname
FROM people
WHERE lname IS NOT NULL;